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<meta name="theme-color" content="#b31b1b">  <title>Search | arXiv e-print repository</title> <script defer src="https://static.arxiv.org/static/base/1.0.0a5/fontawesome-free-5.11.2-web/js/all.js"></script> <link rel="stylesheet" href="https://static.arxiv.org/static/base/1.0.0a5/css/arxivstyle.css" /> <script type="text/x-mathjax-config"> MathJax.Hub.Config({ messageStyle: "none", extensions: ["tex2jax.js"], jax: ["input/TeX", "output/HTML-CSS"], tex2jax: { inlineMath: [ ['$','$'], ["\$","\$"] ], displayMath: [ ['$$','$$'], ["\\[","\\]"] ], processEscapes: true, ignoreClass: '.*', processClass: 'mathjax.*' }, TeX: { extensions: ["AMSmath.js", "AMSsymbols.js", "noErrors.js"], noErrors: { inlineDelimiters: ["$","$"], multiLine: false, style: { "font-size": "normal", "border": "" } } }, "HTML-CSS": { availableFonts: ["TeX"] } }); </script> <script src='//static.arxiv.org/MathJax-2.7.3/MathJax.js'></script> <script 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<button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Golez%2C+D&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Golez%2C+D&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Golez%2C+D&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.22116">arXiv:2410.22116</a> <span> [<a href="https://arxiv.org/pdf/2410.22116">pdf</a>, <a href="https://arxiv.org/format/2410.22116">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Optical signatures of dynamical excitonic condensates </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Osterkorn%2C+A">Alexander Osterkorn</a>, <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Kaneko%2C+T">Tatsuya Kaneko</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhiyuan Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Millis%2C+A+J">Andrew J. Millis</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.22116v1-abstract-short" style="display: inline;"> We theoretically study dynamical excitonic condensates occurring in bilayers with an imposed chemical potential difference and in photodoped semiconductors. We show that optical spectroscopy can experimentally identify phase-trapped and phase-delocalized dynamical regimes of condensation. In the weak-bias regime, the trapped dynamics of the order parameter's phase lead to an in-gap absorption line… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.22116v1-abstract-full').style.display = 'inline'; document.getElementById('2410.22116v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.22116v1-abstract-full" style="display: none;"> We theoretically study dynamical excitonic condensates occurring in bilayers with an imposed chemical potential difference and in photodoped semiconductors. We show that optical spectroscopy can experimentally identify phase-trapped and phase-delocalized dynamical regimes of condensation. In the weak-bias regime, the trapped dynamics of the order parameter's phase lead to an in-gap absorption line at a frequency almost independent of the bias voltage, while for larger biases, the frequency of the spectral feature increases approximately linearly with bias. In both cases there is a pronounced second harmonic response. Close to the transition between the trapped and freely oscillating states, we find a strong response upon application of a weak electric probe field and compare the results to those found in a minimal model description for the dynamics of the order parameter's phase and analyze the limitations of the latter. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.22116v1-abstract-full').style.display = 'none'; document.getElementById('2410.22116v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.06314">arXiv:2409.06314</a> <span> [<a href="https://arxiv.org/pdf/2409.06314">pdf</a>, <a href="https://arxiv.org/format/2409.06314">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Measuring the ultrafast screening of $U$ in photo-excited charge-transfer insulators with time-resolved X-ray absorption spectroscopy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Paprotzki%2C+E">Eva Paprotzki</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2409.06314v1-abstract-short" style="display: inline;"> Recent seminal experiments have utilized time-resolved X-ray absorption spectroscopy (XAS) to investigate the ultrafast photo-induced renormalization of the electron interaction (''Hubbard $U$'') in Mott and charge transfer insulators. In this paper, we analyze the change of interactions due to dynamical screening as it is encoded in the XAS signal, using the non-equilibrium GW+EDMFT formalism. Ou… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.06314v1-abstract-full').style.display = 'inline'; document.getElementById('2409.06314v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.06314v1-abstract-full" style="display: none;"> Recent seminal experiments have utilized time-resolved X-ray absorption spectroscopy (XAS) to investigate the ultrafast photo-induced renormalization of the electron interaction (''Hubbard $U$'') in Mott and charge transfer insulators. In this paper, we analyze the change of interactions due to dynamical screening as it is encoded in the XAS signal, using the non-equilibrium GW+EDMFT formalism. Our study shows that XAS is well-suited for measuring this change, but two aspects should be kept in mind if the screening processes are not substantially faster than the valence electron dynamics: (i) Screening in a photo-excited system can affect both the position and the lineshape of the absorption lines. (ii) In general, the effect cannot be captured by the modification of a single interaction parameter. Specifically, an estimate for $螖U$ extracted from the shift of the XAS lines does not necessarily describe the related shift of the the upper Hubbard band. We clarify these aspects using a minimal cluster model and the three-band Emery model for a charge transfer insulator. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.06314v1-abstract-full').style.display = 'none'; document.getElementById('2409.06314v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.18083">arXiv:2403.18083</a> <span> [<a href="https://arxiv.org/pdf/2403.18083">pdf</a>, <a href="https://arxiv.org/format/2403.18083">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Collective modes and Raman response in Ta$_2$NiSe$_5$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chatterjee%2C+B">Banhi Chatterjee</a>, <a href="/search/cond-mat?searchtype=author&query=Mravlje%2C+J">Jernej Mravlje</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.18083v1-abstract-short" style="display: inline;"> We explore the collective response in an excitonic insulator phase in Ta$_2$NiSe$_5$ using a semirealistic model including relevant lattice and electronic instabilities. We calculate order-parameter susceptibility and Raman response within a time-dependent Hartree-Fock approach. Contrary to the standard expectations, the amplitude mode frequency does not coincide with the single-particle gap but h… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.18083v1-abstract-full').style.display = 'inline'; document.getElementById('2403.18083v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.18083v1-abstract-full" style="display: none;"> We explore the collective response in an excitonic insulator phase in Ta$_2$NiSe$_5$ using a semirealistic model including relevant lattice and electronic instabilities. We calculate order-parameter susceptibility and Raman response within a time-dependent Hartree-Fock approach. Contrary to the standard expectations, the amplitude mode frequency does not coincide with the single-particle gap but has a higher frequency. We find a phase mode that is massive because the excitonic condensation breaks a discrete symmetry only and that becomes heavier as the electron-lattice coupling is increased. These features are expected to apply to generic realistic excitonic insulators. We discuss scenarios under which the phase mode does not appear as a sharp in-gap resonance. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.18083v1-abstract-full').style.display = 'none'; document.getElementById('2403.18083v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.01589">arXiv:2403.01589</a> <span> [<a href="https://arxiv.org/pdf/2403.01589">pdf</a>, <a href="https://arxiv.org/format/2403.01589">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Chirped amplitude mode in photo-excited superconductors </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Blommel%2C+T">Thomas Blommel</a>, <a href="/search/cond-mat?searchtype=author&query=Kaye%2C+J">Jason Kaye</a>, <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Gull%2C+E">Emanuel Gull</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.01589v1-abstract-short" style="display: inline;"> We show that the amplitude mode in superconductors exhibits chirped oscillations under resonant excitation and that the chirping velocity increases as we approach the critical excitation strength. The chirped amplitude mode enables us to determine the local modification of the effective potential even when the system is in a long-lived pre-thermal state. We then show that this chirped amplitude mo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.01589v1-abstract-full').style.display = 'inline'; document.getElementById('2403.01589v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.01589v1-abstract-full" style="display: none;"> We show that the amplitude mode in superconductors exhibits chirped oscillations under resonant excitation and that the chirping velocity increases as we approach the critical excitation strength. The chirped amplitude mode enables us to determine the local modification of the effective potential even when the system is in a long-lived pre-thermal state. We then show that this chirped amplitude mode is an experimentally observable quantity since the photo-induced (super)-current in pump-probe experiments serves as an efficient proxy for the dynamics of the order parameter, including the chirped dynamics. Our result is based on the attractive Hubbard model using dynamical mean-field theory within the symmetry-broken state after a resonant excitation across the superconducting gap. Since the collective response takes place on emergently long timescales, we extend the hierarchical low-rank compression method for nonequilibrium Green's functions to symmetry-broken states and show that it serves as an efficient representation despite long-lived memory kernels. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.01589v1-abstract-full').style.display = 'none'; document.getElementById('2403.01589v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.16988">arXiv:2401.16988</a> <span> [<a href="https://arxiv.org/pdf/2401.16988">pdf</a>, <a href="https://arxiv.org/ps/2401.16988">ps</a>, <a href="https://arxiv.org/format/2401.16988">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Anomalous photo-induced band renormalization in correlated materials: Case study of Ta$_2$NiSe$_5$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Geng%2C+L">Lei Geng</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+X">Xiulan Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+J">Jianing Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Peng%2C+L">Liang-You Peng</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.16988v1-abstract-short" style="display: inline;"> We investigate the anomalous photo-induced band renormalization in correlated materials, exemplified by the case of Ta$_2$NiSe$_5$. The manifestation of this anomaly is characterized by the alternating direction of band shift in response to changes in the laser parameters or electron momentum. We attribute the phenomena to the band inversion of the material and the selective excitation of a high-l… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.16988v1-abstract-full').style.display = 'inline'; document.getElementById('2401.16988v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.16988v1-abstract-full" style="display: none;"> We investigate the anomalous photo-induced band renormalization in correlated materials, exemplified by the case of Ta$_2$NiSe$_5$. The manifestation of this anomaly is characterized by the alternating direction of band shift in response to changes in the laser parameters or electron momentum. We attribute the phenomena to the band inversion of the material and the selective excitation of a high-lying flat band, leading to the competition between the Hartree shift and the order collapse. These findings are based on {\it ab initio} determined effective model for Ta$_2$NiSe$_5$, in which we incorporate high-lying states and the time-dependent GW simulation to follow the non-equilibrium dynamics induced by the laser. Our findings reveal the sensitivity of the non-equilibrium electronic dynamics to the band structure and laser protocols, providing valuable guidance for the selection of suitable materials and lasers in the engineering of band structures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.16988v1-abstract-full').style.display = 'none'; document.getElementById('2401.16988v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.06426">arXiv:2312.06426</a> <span> [<a href="https://arxiv.org/pdf/2312.06426">pdf</a>, <a href="https://arxiv.org/format/2312.06426">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Other Condensed Matter">cond-mat.other</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Dynamical exciton condensates in biased electron-hole bilayers </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhiyuan Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Kaneko%2C+T">Tatsuya Kaneko</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Millis%2C+A+J">Andrew J. Millis</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2312.06426v2-abstract-short" style="display: inline;"> Bilayer materials may support interlayer excitons comprised of electrons in one layer and holes in the other. In experiments, a non-zero exciton density is typically sustained by a bias chemical potential, implemented either by optical pumping or by electrical contacts connected to the two layers. We show that if charge can tunnel between the layers, the chemical potential bias means that an excit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.06426v2-abstract-full').style.display = 'inline'; document.getElementById('2312.06426v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.06426v2-abstract-full" style="display: none;"> Bilayer materials may support interlayer excitons comprised of electrons in one layer and holes in the other. In experiments, a non-zero exciton density is typically sustained by a bias chemical potential, implemented either by optical pumping or by electrical contacts connected to the two layers. We show that if charge can tunnel between the layers, the chemical potential bias means that an exciton condensate is in the dynamical regime of ac Josephson effect. It has physical consequences such as tunneling currents and the ability to tune a condensate from bright (emitting coherent photons) to dark by experimental controlling knobs. If the system is placed in an optical cavity, coupling with cavity photons favors different dynamical states depending on the bias, realizing superradiant phases. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.06426v2-abstract-full').style.display = 'none'; document.getElementById('2312.06426v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 3 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.04899">arXiv:2311.04899</a> <span> [<a href="https://arxiv.org/pdf/2311.04899">pdf</a>, <a href="https://arxiv.org/format/2311.04899">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Floquet engineering of binding in doped and photo-doped Mott insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Sarkar%2C+M">Madhumita Sarkar</a>, <a href="/search/cond-mat?searchtype=author&query=Lenar%C4%8Di%C4%8D%2C+Z">Zala Lenar膷i膷</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2311.04899v2-abstract-short" style="display: inline;"> We investigate the emergence of bound states in chemically and photo-doped Mott insulators, mediated by spin and $畏$-pairing fluctuations within both 2-leg ladder and 2D systems. To effectively describe the photo and chemically doped state on the same footings, we employ the Schrieffer-Wolff transformation, resulting in a generalized $t$-$J$ model. Our results demonstrate that the binding energies… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.04899v2-abstract-full').style.display = 'inline'; document.getElementById('2311.04899v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.04899v2-abstract-full" style="display: none;"> We investigate the emergence of bound states in chemically and photo-doped Mott insulators, mediated by spin and $畏$-pairing fluctuations within both 2-leg ladder and 2D systems. To effectively describe the photo and chemically doped state on the same footings, we employ the Schrieffer-Wolff transformation, resulting in a generalized $t$-$J$ model. Our results demonstrate that the binding energies and localization length in the chemically and photo-doped regimes are comparable, with $畏$-pairing fluctuations not playing a crucial role. Furthermore, we show that manipulating the binding is possible through external periodic driving, a technique known as Floquet engineering, leading to significantly enhanced binding energies. We also roughly estimate the lifetime of photo-doped states under periodic driving conditions based on the Fermi golden rule. Lastly, we propose experimental protocols for realizing Hubbard excitons in cold-atom experiments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.04899v2-abstract-full').style.display = 'none'; document.getElementById('2311.04899v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 14 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.05201">arXiv:2310.05201</a> <span> [<a href="https://arxiv.org/pdf/2310.05201">pdf</a>, <a href="https://arxiv.org/format/2310.05201">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Photo-induced nonequilibrium states in Mott insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2310.05201v1-abstract-short" style="display: inline;"> The study of nonequilibrium phenomena in interacting lattice systems can provide new perspectives on correlation effects, and information on metastable states of matter. Mott insulators are a promising class of systems for nonequilibrium studies, since they exhibit exotic phenomena and complex phase diagrams upon doping, and because a large Mott gap provides protection against fast thermalization… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.05201v1-abstract-full').style.display = 'inline'; document.getElementById('2310.05201v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.05201v1-abstract-full" style="display: none;"> The study of nonequilibrium phenomena in interacting lattice systems can provide new perspectives on correlation effects, and information on metastable states of matter. Mott insulators are a promising class of systems for nonequilibrium studies, since they exhibit exotic phenomena and complex phase diagrams upon doping, and because a large Mott gap provides protection against fast thermalization and heating after photo-excitations. We can thus expect the emergence of interesting transient states and photo-induced phases in Mott systems. This review presents the current understanding of the mechanisms which control the time evolution of photo-doped charge carriers and the properties of photo-induced metastable states. We focus on recent theoretical progress, identify the relevant underlying concepts, and link them to experimental observations. The review starts with a general discussion of field-induced nonequilibrium setups and an overview of key experiments which revealed characteristic properties of photo-excited Mott states, proceeds with a compact overview of the theoretical tools which have been developed to investigate these strongly correlated nonequilibrium states, and then analyzes Mott insulators driven out of equilibrium by static electric fields, periodic fields, and short laser pulses. We also discuss the appearance of nonthermal electronic orders in photo-excited Mott systems, including nonthermal spin and orbital orders, $畏$ pairing states, and novel types of excitonic orders. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.05201v1-abstract-full').style.display = 'none'; document.getElementById('2310.05201v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Review article</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.03309">arXiv:2308.03309</a> <span> [<a href="https://arxiv.org/pdf/2308.03309">pdf</a>, <a href="https://arxiv.org/format/2308.03309">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.108.205121">10.1103/PhysRevB.108.205121 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Exciton-spin interactions in antiferromagnetic charge-transfer insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kaneko%2C+T">Tatsuya Kaneko</a>, <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhiyuan Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Millis%2C+A+J">Andrew J. Millis</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.03309v2-abstract-short" style="display: inline;"> We derive exciton-spin interactions from a microscopic correlated model that captures important aspects of the physics of charge-transfer (CT) insulators to address magnetism associated with exciton creation. We present a minimal model consisting of coupled clusters of transition metal d and ligand p orbitals that captures the essential features of the local atomic and electronic structure. First,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.03309v2-abstract-full').style.display = 'inline'; document.getElementById('2308.03309v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.03309v2-abstract-full" style="display: none;"> We derive exciton-spin interactions from a microscopic correlated model that captures important aspects of the physics of charge-transfer (CT) insulators to address magnetism associated with exciton creation. We present a minimal model consisting of coupled clusters of transition metal d and ligand p orbitals that captures the essential features of the local atomic and electronic structure. First, we identify the lowest-energy state and optically allowed excited states within a cluster by applying the molecular orbital picture to the ligand p orbitals. Then, we derive the effective interactions between two clusters mediated by intercluster hoppings, which include exciton-spin couplings. The interplay of the correlations and the spatial structure of the CT exciton leads to strong magnetic exchange couplings with spatial anisotropy. Finally, we calculate an optical excitation spectrum in our effective model to obtain insights into magnetic sidebands optically observed in magnetic materials. We demonstrate that the spin-flip excitation due to the strongly enhanced local spin interactions around the exciton gives rise to the magnetic sidebands. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.03309v2-abstract-full').style.display = 'none'; document.getElementById('2308.03309v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 8 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 108, 205121 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.08566">arXiv:2307.08566</a> <span> [<a href="https://arxiv.org/pdf/2307.08566">pdf</a>, <a href="https://arxiv.org/format/2307.08566">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Numerical Analysis">math.NA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevX.14.031034">10.1103/PhysRevX.14.031034 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Decomposing imaginary time Feynman diagrams using separable basis functions: Anderson impurity model strong coupling expansion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kaye%2C+J">Jason Kaye</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+Z">Zhen Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Strand%2C+H+U+R">Hugo U. R. Strand</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2307.08566v3-abstract-short" style="display: inline;"> We present a deterministic algorithm for the efficient evaluation of imaginary time diagrams based on the recently introduced discrete Lehmann representation (DLR) of imaginary time Green's functions. In addition to the efficient discretization of diagrammatic integrals afforded by its approximation properties, the DLR basis is separable in imaginary time, allowing us to decompose diagrams into li… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.08566v3-abstract-full').style.display = 'inline'; document.getElementById('2307.08566v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.08566v3-abstract-full" style="display: none;"> We present a deterministic algorithm for the efficient evaluation of imaginary time diagrams based on the recently introduced discrete Lehmann representation (DLR) of imaginary time Green's functions. In addition to the efficient discretization of diagrammatic integrals afforded by its approximation properties, the DLR basis is separable in imaginary time, allowing us to decompose diagrams into linear combinations of nested sequences of one-dimensional products and convolutions. Focusing on the strong coupling bold-line expansion of generalized Anderson impurity models, we show that our strategy reduces the computational complexity of evaluating an $M$th-order diagram at inverse temperature $尾$ and spectral width $蠅_{\max}$ from $\mathcal{O}((尾蠅_{\max})^{2M-1})$ for a direct quadrature to $\mathcal{O}(M (\log (尾蠅_{\max}))^{M+1})$, with controllable high-order accuracy. We benchmark our algorithm using third-order expansions for multi-band impurity problems with off-diagonal hybridization and spin-orbit coupling, presenting comparisons with exact diagonalization and quantum Monte Carlo approaches. In particular, we perform a self-consistent dynamical mean-field theory calculation for a three-band Hubbard model with strong spin-orbit coupling representing a minimal model of Ca$_2$RuO$_4$, demonstrating the promise of the method for modeling realistic strongly correlated multi-band materials. For both strong and weak coupling expansions of low and intermediate order, in which diagrams can be enumerated, our method provides an efficient, straightforward, and robust black-box evaluation procedure. In this sense, it fills a gap between diagrammatic approximations of the lowest order, which are simple and inexpensive but inaccurate, and those based on Monte Carlo sampling of high-order diagrams. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.08566v3-abstract-full').style.display = 'none'; document.getElementById('2307.08566v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. X 14, 031034 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.10145">arXiv:2305.10145</a> <span> [<a href="https://arxiv.org/pdf/2305.10145">pdf</a>, <a href="https://arxiv.org/format/2305.10145">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.110.245120">10.1103/PhysRevB.110.245120 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Photo-induced charge-transfer renormalization in NiO </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lojewski%2C+T">Tobias Lojewski</a>, <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Ollefs%2C+K">Katharina Ollefs</a>, <a href="/search/cond-mat?searchtype=author&query=Guyader%2C+L+L">Lo茂c Le Guyader</a>, <a href="/search/cond-mat?searchtype=author&query=K%C3%A4mmerer%2C+L">Lea K盲mmerer</a>, <a href="/search/cond-mat?searchtype=author&query=Rothenbach%2C+N">Nico Rothenbach</a>, <a href="/search/cond-mat?searchtype=author&query=Engel%2C+R+Y">Robin Y. Engel</a>, <a href="/search/cond-mat?searchtype=author&query=Miedema%2C+P+S">Piter S. Miedema</a>, <a href="/search/cond-mat?searchtype=author&query=Beye%2C+M">Martin Beye</a>, <a href="/search/cond-mat?searchtype=author&query=Chiuzb%C4%83ian%2C+G+S">Gheorghe S. Chiuzb膬ian</a>, <a href="/search/cond-mat?searchtype=author&query=Carley%2C+R">Robert Carley</a>, <a href="/search/cond-mat?searchtype=author&query=Gort%2C+R">Rafael Gort</a>, <a href="/search/cond-mat?searchtype=author&query=Van+Kuiken%2C+B+E">Benjamin E. Van Kuiken</a>, <a href="/search/cond-mat?searchtype=author&query=Mercurio%2C+G">Giuseppe Mercurio</a>, <a href="/search/cond-mat?searchtype=author&query=Schlappa%2C+J">Justina Schlappa</a>, <a href="/search/cond-mat?searchtype=author&query=Yaroslavtsev%2C+A">Alexander Yaroslavtsev</a>, <a href="/search/cond-mat?searchtype=author&query=Scherz%2C+A">Andreas Scherz</a>, <a href="/search/cond-mat?searchtype=author&query=D%C3%B6ring%2C+F">Florian D枚ring</a>, <a href="/search/cond-mat?searchtype=author&query=David%2C+C">Christian David</a>, <a href="/search/cond-mat?searchtype=author&query=Wende%2C+H">Heiko Wende</a>, <a href="/search/cond-mat?searchtype=author&query=Bovensiepen%2C+U">Uwe Bovensiepen</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Eschenlohr%2C+A">Andrea Eschenlohr</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2305.10145v2-abstract-short" style="display: inline;"> Photo-doped states in strongly correlated charge transfer insulators are characterized by $d$-$d$ and $d$-$p$ interactions and the resulting intertwined dynamics of charge excitations and local multiplets. Here we use femtosecond x-ray absorption spectroscopy in combination with dynamical mean-field theory to disentangle these contributions in NiO. Upon resonant optical excitation across the charg… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.10145v2-abstract-full').style.display = 'inline'; document.getElementById('2305.10145v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.10145v2-abstract-full" style="display: none;"> Photo-doped states in strongly correlated charge transfer insulators are characterized by $d$-$d$ and $d$-$p$ interactions and the resulting intertwined dynamics of charge excitations and local multiplets. Here we use femtosecond x-ray absorption spectroscopy in combination with dynamical mean-field theory to disentangle these contributions in NiO. Upon resonant optical excitation across the charge transfer gap, the Ni $L_3$ and O $K$ absorption edges red-shift for $>10$ ps, associated with photo-induced changes in the screening environment. An additional signature below the Ni $L_3$ edge is identified for $<1$ ps, reflecting a transient nonthermal population of local many-body multiplets. We employ a nonthermal generalization of the multiplet ligand field theory to show that the feature originates from $d$-$d$ transitions. Overall, the photo-doped state differs significantly from a chemically doped state. Our results demonstrate the ability to reveal excitation pathways in correlated materials by x-ray spectroscopies, which is relevant for ultrafast materials design. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.10145v2-abstract-full').style.display = 'none'; document.getElementById('2305.10145v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 110, 245120 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.09238">arXiv:2305.09238</a> <span> [<a href="https://arxiv.org/pdf/2305.09238">pdf</a>, <a href="https://arxiv.org/format/2305.09238">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.132.106001">10.1103/PhysRevLett.132.106001 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optical manipulation of bipolarons in a system with nonlinear electron-phonon coupling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kova%C4%8D%2C+K">K. Kova膷</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">D. Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Mierzejewski%2C+M">M. Mierzejewski</a>, <a href="/search/cond-mat?searchtype=author&query=Bon%C4%8Da%2C+J">J. Bon膷a</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2305.09238v3-abstract-short" style="display: inline;"> We investigate full quantum mechanical evolution of two electrons nonlinearly coupled to quantum phonons and simulate the dynamical response of the system subject to a short spatially uniform optical pulse that couples to dipole-active vibrational modes. Nonlinear electron-phonon coupling can either soften or stiffen the phonon frequency in the presence of electron density. In the former case, an… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.09238v3-abstract-full').style.display = 'inline'; document.getElementById('2305.09238v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.09238v3-abstract-full" style="display: none;"> We investigate full quantum mechanical evolution of two electrons nonlinearly coupled to quantum phonons and simulate the dynamical response of the system subject to a short spatially uniform optical pulse that couples to dipole-active vibrational modes. Nonlinear electron-phonon coupling can either soften or stiffen the phonon frequency in the presence of electron density. In the former case, an external optical pulse tuned just below the phonon frequency generates attraction between electrons and leads to a long-lived bound state even after the optical pulse is switched off. It originates from a dynamical modification of the self-trapping potential that induces a metastable state. By increasing the pulse frequency, the attractive electron-electron interaction changes to repulsive. Two sequential optical pulses with different frequencies can switch between attractive and repulsive interaction. Finally, we show that the pulse-induced binding of electrons is shown to be efficient also for weakly dispersive optical phonons, in the presence anharmonic phonon spectrum and in two dimensions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.09238v3-abstract-full').style.display = 'none'; document.getElementById('2305.09238v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.02149">arXiv:2304.02149</a> <span> [<a href="https://arxiv.org/pdf/2304.02149">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Picosecond volume expansion drives a later-time insulator-metal transition in a nano-textured Mott Insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Verma%2C+A">Anita Verma</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Gorobtsov%2C+O+Y">Oleg Yu. Gorobtsov</a>, <a href="/search/cond-mat?searchtype=author&query=Kaj%2C+K">Kelson Kaj</a>, <a href="/search/cond-mat?searchtype=author&query=Russell%2C+R">Ryan Russell</a>, <a href="/search/cond-mat?searchtype=author&query=Kaaret%2C+J+Z">Jeffrey Z. Kaaret</a>, <a href="/search/cond-mat?searchtype=author&query=Lamb%2C+E">Erik Lamb</a>, <a href="/search/cond-mat?searchtype=author&query=Khalsa%2C+G">Guru Khalsa</a>, <a href="/search/cond-mat?searchtype=author&query=Nair%2C+H+P">Hari P Nair</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Y">Yifei Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Bouck%2C+R">Ryan Bouck</a>, <a href="/search/cond-mat?searchtype=author&query=Schreiber%2C+N">Nathaniel Schreiber</a>, <a href="/search/cond-mat?searchtype=author&query=Ruf%2C+J+P">Jacob P. Ruf</a>, <a href="/search/cond-mat?searchtype=author&query=Ramaprasad%2C+V">Varun Ramaprasad</a>, <a href="/search/cond-mat?searchtype=author&query=Kubota%2C+Y">Yuya Kubota</a>, <a href="/search/cond-mat?searchtype=author&query=Togashi%2C+T">Tadashi Togashi</a>, <a href="/search/cond-mat?searchtype=author&query=Stoica%2C+V+A">Vladimir A. Stoica</a>, <a href="/search/cond-mat?searchtype=author&query=Padmanabhan%2C+H">Hari Padmanabhan</a>, <a href="/search/cond-mat?searchtype=author&query=Freeland%2C+J+W">John W. Freeland</a>, <a href="/search/cond-mat?searchtype=author&query=Benedek%2C+N+A">Nicole A. Benedek</a>, <a href="/search/cond-mat?searchtype=author&query=Shpyrko%2C+O">Oleg Shpyrko</a>, <a href="/search/cond-mat?searchtype=author&query=Harter%2C+J+W">John W. Harter</a>, <a href="/search/cond-mat?searchtype=author&query=Averitt%2C+R+D">Richard D. Averitt</a>, <a href="/search/cond-mat?searchtype=author&query=Schlom%2C+D+G">Darrell G. Schlom</a>, <a href="/search/cond-mat?searchtype=author&query=Shen%2C+K+M">Kyle M. Shen</a> , et al. (2 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2304.02149v2-abstract-short" style="display: inline;"> Technology moves towards ever faster switching between different electronic and magnetic states of matter. Manipulating properties at terahertz rates requires accessing the intrinsic timescales of electrons (femtoseconds) and associated phonons (10s of femtoseconds to few picoseconds), which is possible with short-pulse photoexcitation. Yet, in many Mott insulators, the electronic transition is ac… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.02149v2-abstract-full').style.display = 'inline'; document.getElementById('2304.02149v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.02149v2-abstract-full" style="display: none;"> Technology moves towards ever faster switching between different electronic and magnetic states of matter. Manipulating properties at terahertz rates requires accessing the intrinsic timescales of electrons (femtoseconds) and associated phonons (10s of femtoseconds to few picoseconds), which is possible with short-pulse photoexcitation. Yet, in many Mott insulators, the electronic transition is accompanied by the nucleation and growth of percolating domains of the changed lattice structure, leading to empirical time scales dominated by slow coarsening dynamics. Here, we use time-resolved X-ray diffraction and reflectivity measurements to investigate the photoinduced insulator-to-metal transition in an epitaxially strained thin film Mott insulator Ca2RuO4. The dynamical transition occurs without observable domain formation and coarsening effects, allowing the study of the intrinsic electronic and lattice dynamics. Above a fluence threshold, the initial electronic excitation drives a fast lattice rearrangement, followed by a slower electronic evolution into a metastable non-equilibrium state. Microscopic calculations based on time-dependent dynamical mean-field theory and semiclassical lattice dynamics within a recently published equilibrium energy landscape picture explain the threshold-behavior and elucidate the delayed onset of the electronic phase transition in terms of kinematic constraints on recombination. Analysis of satellite scattering peaks indicates the persistence of a strain-induced nano-texture in the photoexcited film. This work highlights the importance of combined electronic and structural studies to unravel the physics of dynamic transitions and elucidates the role of strain in tuning the timescales of photoinduced processes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.02149v2-abstract-full').style.display = 'none'; document.getElementById('2304.02149v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.06762">arXiv:2204.06762</a> <span> [<a href="https://arxiv.org/pdf/2204.06762">pdf</a>, <a href="https://arxiv.org/ps/2204.06762">ps</a>, <a href="https://arxiv.org/format/2204.06762">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.106.165106">10.1103/PhysRevB.106.165106 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Local interpretation of time-resolved X-ray absorption in Mott insulators: Insights from nonequilibrium dynamical mean-field theory </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2204.06762v2-abstract-short" style="display: inline;"> We present a formalism based on nonequilibrium dynamical mean field theory (DMFT) which allows to compute the time-resolved X-ray absorption spectrum (XAS) of photo-excited solids. By applying this formalism to the photo-doped half-filled and quarter-filled two-orbital Hubbard models in the Mott insulating regime we clarify how the time-resolved XAS signal reflects the nonequilibrium population of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.06762v2-abstract-full').style.display = 'inline'; document.getElementById('2204.06762v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.06762v2-abstract-full" style="display: none;"> We present a formalism based on nonequilibrium dynamical mean field theory (DMFT) which allows to compute the time-resolved X-ray absorption spectrum (XAS) of photo-excited solids. By applying this formalism to the photo-doped half-filled and quarter-filled two-orbital Hubbard models in the Mott insulating regime we clarify how the time-resolved XAS signal reflects the nonequilibrium population of different local states. Apart from the missing broadening associated with continuum excitations, the atomic XAS spectrum computed with the nonthermal state populations provides a good approximation to the full nonequilibrium DMFT result. This suggest a route to combine the accurate DMFT description of nonequilibrum states of solids with cluster calculations of the XAS signal. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.06762v2-abstract-full').style.display = 'none'; document.getElementById('2204.06762v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> Phys. Rev. B 106, 165106 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2112.06298">arXiv:2112.06298</a> <span> [<a href="https://arxiv.org/pdf/2112.06298">pdf</a>, <a href="https://arxiv.org/format/2112.06298">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.106.L121106">10.1103/PhysRevB.106.L121106 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Unveiling the underlying interactions in Ta2NiSe5 from photo-induced lifetime change </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Dufresne%2C+S+K+Y">Sydney K. Y. Dufresne</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+M">Min-Jae Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Boschini%2C+F">Fabio Boschini</a>, <a href="/search/cond-mat?searchtype=author&query=Chu%2C+H">Hao Chu</a>, <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Levy%2C+G">Giorgio Levy</a>, <a href="/search/cond-mat?searchtype=author&query=Mills%2C+A+K">Arthur K. Mills</a>, <a href="/search/cond-mat?searchtype=author&query=Zhdanovich%2C+S">Sergey Zhdanovich</a>, <a href="/search/cond-mat?searchtype=author&query=Isobe%2C+M">Masahiko Isobe</a>, <a href="/search/cond-mat?searchtype=author&query=Takagi%2C+H">Hidenori Takagi</a>, <a href="/search/cond-mat?searchtype=author&query=Kaiser%2C+S">Stefan Kaiser</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Jones%2C+D+J">David J. Jones</a>, <a href="/search/cond-mat?searchtype=author&query=Georges%2C+A">Antoine Georges</a>, <a href="/search/cond-mat?searchtype=author&query=Damascelli%2C+A">Andrea Damascelli</a>, <a href="/search/cond-mat?searchtype=author&query=Millis%2C+A+J">Andrew J. Millis</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2112.06298v1-abstract-short" style="display: inline;"> We present a generic procedure for quantifying the interplay of electronic and lattice degrees of freedom in photo-doped insulators through a comparative analysis of theoretical many-body simulations and time- and angle-resolved photoemission spectroscopy (TR-ARPES) of the transient response of the candidate excitonic insulator Ta2NiSe5. Our analysis demonstrates that the electron-electron interac… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.06298v1-abstract-full').style.display = 'inline'; document.getElementById('2112.06298v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2112.06298v1-abstract-full" style="display: none;"> We present a generic procedure for quantifying the interplay of electronic and lattice degrees of freedom in photo-doped insulators through a comparative analysis of theoretical many-body simulations and time- and angle-resolved photoemission spectroscopy (TR-ARPES) of the transient response of the candidate excitonic insulator Ta2NiSe5. Our analysis demonstrates that the electron-electron interactions dominate the electron-phonon ones. In particular, a detailed analysis of the TRARPES spectrum enables a clear separation of the dominant broadening (electronic lifetime) effects from the much smaller bandgap renormalization. Theoretical calculations show that the observed strong spectral broadening arises from the electronic scattering of the photo-excited particle-hole pairs and cannot be accounted for in a model in which electron-phonon interactions are dominant. We demonstrate that the magnitude of the weaker subdominant bandgap renormalization sensitively depends on the distance from the semiconductor/semimetal transition in the high-temperature state, which could explain apparent contradictions between various TR-ARPES experiments. The analysis presented here indicates that electron-electron interactions play a vital role (although not necessarily the sole one) in stabilizing the insulating state. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.06298v1-abstract-full').style.display = 'none'; document.getElementById('2112.06298v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 December, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2106.07008">arXiv:2106.07008</a> <span> [<a href="https://arxiv.org/pdf/2106.07008">pdf</a>, <a href="https://arxiv.org/ps/2106.07008">ps</a>, <a href="https://arxiv.org/format/2106.07008">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.104.115138">10.1103/PhysRevB.104.115138 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Photo-induced Dirac cone flattening in BaNiS$_2$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Bittner%2C+N">Nikolaj Bittner</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Casula%2C+M">Michele Casula</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2106.07008v1-abstract-short" style="display: inline;"> Using a real-time implementation of the self-consistent $GW$ method, we theoretically investigate the photo-induced changes in the electronic structure of the quasi two-dimensional semi-metal BaNiS$_2$. This material features four Dirac cones in the unit cell and our simulation of the time- and momentum-resolved nonequilibrium spectral function reveals a flattening of the Dirac bands after a photo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.07008v1-abstract-full').style.display = 'inline'; document.getElementById('2106.07008v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.07008v1-abstract-full" style="display: none;"> Using a real-time implementation of the self-consistent $GW$ method, we theoretically investigate the photo-induced changes in the electronic structure of the quasi two-dimensional semi-metal BaNiS$_2$. This material features four Dirac cones in the unit cell and our simulation of the time- and momentum-resolved nonequilibrium spectral function reveals a flattening of the Dirac bands after a photo-doping pulse with a 1.5 eV laser. The simulation results are consistent with the recently reported experimental data on photo-doped BaNiS$_2$ and ZrSiSe, another Dirac semi-metal. A detailed analysis of the numerical data allows us to attribute the nonequilibrium modifications of the Dirac bands to (i) an increased effective temperature after the photo-excitation, which affects the screening properties of the system, and (ii) to nontrivial band shifts in the photo-doped state, which are mainly induced by the Fock term. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.07008v1-abstract-full').style.display = 'none'; document.getElementById('2106.07008v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 104, 115138 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2105.13560">arXiv:2105.13560</a> <span> [<a href="https://arxiv.org/pdf/2105.13560">pdf</a>, <a href="https://arxiv.org/format/2105.13560">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s42005-021-00799-7">10.1038/s42005-021-00799-7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Exploring nonequilibrium phases of photo-doped Mott insulators with Generalized Gibbs ensembles </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Takayoshi%2C+S">Shintaro Takayoshi</a>, <a href="/search/cond-mat?searchtype=author&query=Kaneko%2C+T">Tatsuya Kaneko</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhiyuan Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Millis%2C+A+J">Andrew J. Millis</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2105.13560v2-abstract-short" style="display: inline;"> Photo-excited strongly correlated systems can exhibit intriguing non-thermal phases, but the theoretical investigation of them poses significant challenges. In this work, we introduce a generalized Gibbs ensemble type description for long-lived photo-doped states in Mott insulators. This framework enables systematic studies of photo-induced phases based on equilibrium methods, as demonstrated here… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.13560v2-abstract-full').style.display = 'inline'; document.getElementById('2105.13560v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2105.13560v2-abstract-full" style="display: none;"> Photo-excited strongly correlated systems can exhibit intriguing non-thermal phases, but the theoretical investigation of them poses significant challenges. In this work, we introduce a generalized Gibbs ensemble type description for long-lived photo-doped states in Mott insulators. This framework enables systematic studies of photo-induced phases based on equilibrium methods, as demonstrated here for the one-dimensional extended Hubbard model. We determine the nonequilibrium phase diagram, which features $畏$-pairing and charge density wave phases in a wide doping range, and reveal physical properties of these phases. We show that the peculiar kinematics of photo-doped carriers, and the interaction between them, play an essential role in the formation of the non-thermal phases, and we clarify the differences between photo-doped Mott insulators, chemically-doped Mott insulators and photo-doped semiconductors. Our results demonstrate a new path for the systematic exploration of nonequilibrium strongly correlated systems and show that photo-doped Mott insulators host different phases than conventional semiconductors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.13560v2-abstract-full').style.display = 'none'; document.getElementById('2105.13560v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 December, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 May, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8page,4 figures + 8page, 16 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Communications Physics 5, 23 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.10455">arXiv:2102.10455</a> <span> [<a href="https://arxiv.org/pdf/2102.10455">pdf</a>, <a href="https://arxiv.org/format/2102.10455">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Gases">cond-mat.quant-gas</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.127.127702">10.1103/PhysRevLett.127.127702 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Second order Josephson effect in excitonic insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhiyuan Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Kaneko%2C+T">Tatsuya Kaneko</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Millis%2C+A+J">Andrew J. Millis</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2102.10455v2-abstract-short" style="display: inline;"> We show that in electron-hole bilayers with excitonic order arising from conduction and valence bands formed by atomic orbitals that have different parities, nonzero interlayer tunneling leads to a second order Josephson effect. This means the interlayer electrical current is related to the phase of the excitonic order parameter as $J = J_c \sin2胃$ instead of $J = J_c \sin 胃$, and that the system… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.10455v2-abstract-full').style.display = 'inline'; document.getElementById('2102.10455v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.10455v2-abstract-full" style="display: none;"> We show that in electron-hole bilayers with excitonic order arising from conduction and valence bands formed by atomic orbitals that have different parities, nonzero interlayer tunneling leads to a second order Josephson effect. This means the interlayer electrical current is related to the phase of the excitonic order parameter as $J = J_c \sin2胃$ instead of $J = J_c \sin 胃$, and that the system has two degenerate ground states at $胃=0, 蟺$ that can be switched by an interlayer voltage pulse. When generalized to a three dimensional stack of alternating electron-hole planes or a two dimensional stack of chains, AC Josephson effect implies that electric field pulses perpendicular to the layers and chains can steer the order parameter phase between the two degenerate ground states, making these devices ultrafast memories. The order parameter steering also applies to the excitonic insulator candidate Ta$_2$NiSe$_5$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.10455v2-abstract-full').style.display = 'none'; document.getElementById('2102.10455v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 pages, 2 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 127, 127702 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.06510">arXiv:2102.06510</a> <span> [<a href="https://arxiv.org/pdf/2102.06510">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-021-24073-0">10.1038/s41467-021-24073-0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum billiards with correlated electrons confined in triangular transition metal dichalcogenide monolayer nanostructures created by laser quench </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ravnik%2C+J">Jan Ravnik</a>, <a href="/search/cond-mat?searchtype=author&query=Vaskivskyi%2C+Y">Yevhenii Vaskivskyi</a>, <a href="/search/cond-mat?searchtype=author&query=Vodeb%2C+J">Jaka Vodeb</a>, <a href="/search/cond-mat?searchtype=author&query=Aupi%C4%8D%2C+P">Polona Aupi膷</a>, <a href="/search/cond-mat?searchtype=author&query=Vaskivskyi%2C+I">Igor Vaskivskyi</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Gerasimenko%2C+Y">Yaroslav Gerasimenko</a>, <a href="/search/cond-mat?searchtype=author&query=Kabanov%2C+V">Viktor Kabanov</a>, <a href="/search/cond-mat?searchtype=author&query=Mihailovic%2C+D">Dragan Mihailovic</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2102.06510v1-abstract-short" style="display: inline;"> Forcing systems though fast non-equilibrium phase transitions offers the opportunity to study new states of quantum matter that self-assemble in their wake. Here we study the quantum interference effects of correlated electrons confined in monolayer quantum nanostructures, created by femtosecond laser-induced quench through a first-order polytype structural transition in a layered transition-metal… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.06510v1-abstract-full').style.display = 'inline'; document.getElementById('2102.06510v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.06510v1-abstract-full" style="display: none;"> Forcing systems though fast non-equilibrium phase transitions offers the opportunity to study new states of quantum matter that self-assemble in their wake. Here we study the quantum interference effects of correlated electrons confined in monolayer quantum nanostructures, created by femtosecond laser-induced quench through a first-order polytype structural transition in a layered transition-metal dichalcogenide material. Scanning tunnelling microscopy of the electrons confined within equilateral triangles, whose dimensions are a few crystal unit cells on the side, reveals that the trajectories are strongly modified from free-electron states both by electronic correlations and confinement. Comparison of experiments with theoretical predictions of strongly correlated electron behaviour reveals that the confining geometry destabilizes the Wigner/Mott crystal ground state, resulting in mixed itinerant and correlation-localized states intertwined on a length scale of 1 nm. Occasionally, itinerant-electron states appear to follow quantum interferences which are suggestive of classical trajectories (quantum scars). The work opens the path toward understanding the quantum transport of electrons confined in atomic-scale monolayer structures based on correlated-electron-materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.06510v1-abstract-full').style.display = 'none'; document.getElementById('2102.06510v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat Commun 12, 3793 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.03202">arXiv:2101.03202</a> <span> [<a href="https://arxiv.org/pdf/2101.03202">pdf</a>, <a href="https://arxiv.org/format/2101.03202">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.103.144304">10.1103/PhysRevB.103.144304 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Photo-induced phase transition and associated time scales in the excitonic insulator Ta$_2$NiSe$_5$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Saha%2C+T">Tanusree Saha</a>, <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=De+Ninno%2C+G">Giovanni De Ninno</a>, <a href="/search/cond-mat?searchtype=author&query=Mravlje%2C+J">Jernej Mravlje</a>, <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Ressel%2C+B">Barbara Ressel</a>, <a href="/search/cond-mat?searchtype=author&query=Stupar%2C+M">Matija Stupar</a>, <a href="/search/cond-mat?searchtype=author&query=Ribic%2C+P+R">Primoz Rebernik Ribic</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2101.03202v1-abstract-short" style="display: inline;"> We investigate the non-equilibrium electronic structure and characteristic time scales in a candidate excitonic insulator, Ta$_2$NiSe$_5$, using time- and angle-resolved photoemission spectroscopy with a temporal resolution of 50 fs. Following a strong photoexcitation, the band gap closes transiently within 100 fs, i.e., on a time scale faster than the typical lattice vibrational period. Furthermo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.03202v1-abstract-full').style.display = 'inline'; document.getElementById('2101.03202v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.03202v1-abstract-full" style="display: none;"> We investigate the non-equilibrium electronic structure and characteristic time scales in a candidate excitonic insulator, Ta$_2$NiSe$_5$, using time- and angle-resolved photoemission spectroscopy with a temporal resolution of 50 fs. Following a strong photoexcitation, the band gap closes transiently within 100 fs, i.e., on a time scale faster than the typical lattice vibrational period. Furthermore, we find that the characteristic time associated with the rise of the photoemission intensity above the Fermi energy decreases with increasing excitation strength, while the relaxation time of the electron population towards equilibrium shows an opposite behaviour. We argue that these experimental observations can be consistently explained by an excitonic origin of the band gap in the material. The excitonic picture is supported by microscopic calculations based on the non-equilibrium Green's function formalism for an interacting two-band system. We interpret the speedup of the rise time with fluence in terms of an enhanced scattering probability between photo-excited electrons and excitons, leading to an initially faster decay of the order parameter. We show that the inclusion of electron-phonon coupling at a semi-classical level changes only the quantitative aspects of the proposed dynamics, while the qualitative features remain the same. The experimental observations and microscopic calculations allow us to develop a simple and intuitive phenomenological model that captures the main dynamics after photoexcitation in Ta$_2$NiSe$_5$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.03202v1-abstract-full').style.display = 'none'; document.getElementById('2101.03202v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 103, 144304 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.09786">arXiv:2012.09786</a> <span> [<a href="https://arxiv.org/pdf/2012.09786">pdf</a>, <a href="https://arxiv.org/format/2012.09786">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.127.127402">10.1103/PhysRevLett.127.127402 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Bulk Photovoltaic Effect Driven by Collective Excitations in a Correlated Insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kaneko%2C+T">Tatsuya Kaneko</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhiyuan Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Millis%2C+A+J">Andrew J. Millis</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2012.09786v2-abstract-short" style="display: inline;"> We investigate the bulk photovoltaic effect, which rectifies light into electric current, in a collective quantum state with correlation driven electronic ferroelectricity. We show via explicit real-time dynamical calculations that the effect of the applied electric field on the electronic order parameter leads to a strong enhancement of the bulk photovoltaic effect relative to the values obtained… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.09786v2-abstract-full').style.display = 'inline'; document.getElementById('2012.09786v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.09786v2-abstract-full" style="display: none;"> We investigate the bulk photovoltaic effect, which rectifies light into electric current, in a collective quantum state with correlation driven electronic ferroelectricity. We show via explicit real-time dynamical calculations that the effect of the applied electric field on the electronic order parameter leads to a strong enhancement of the bulk photovoltaic effect relative to the values obtained in a conventional insulator. The enhancements include both resonant enhancements at sub-band-gap frequencies, arising from excitation of optically active collective modes, and broadband enhancements arising from nonresonant deformations of the electronic order. The deformable electronic order parameter produces an injection current contribution to the bulk photovoltaic effect that is entirely absent in a rigid-band approximation to a time-reversal symmetric material. Our findings establish that correlation effects can lead to the bulk photovoltaic effect and demonstrate that the collective behavior of ordered states can yield large nonlinear optical responses. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.09786v2-abstract-full').style.display = 'none'; document.getElementById('2012.09786v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 11 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 127, 127402 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2010.06511">arXiv:2010.06511</a> <span> [<a href="https://arxiv.org/pdf/2010.06511">pdf</a>, <a href="https://arxiv.org/format/2010.06511">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Computational Physics">physics.comp-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.21468/SciPostPhys.10.4.091">10.21468/SciPostPhys.10.4.091 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Low rank compression in the numerical solution of the nonequilibrium Dyson equation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kaye%2C+J">Jason Kaye</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2010.06511v3-abstract-short" style="display: inline;"> We propose a method to improve the computational and memory efficiency of numerical solvers for the nonequilibrium Dyson equation in the Keldysh formalism. It is based on the empirical observation that the nonequilibrium Green's functions and self energies arising in many problems of physical interest, discretized as matrices, have low rank off-diagonal blocks, and can therefore be compressed usin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.06511v3-abstract-full').style.display = 'inline'; document.getElementById('2010.06511v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.06511v3-abstract-full" style="display: none;"> We propose a method to improve the computational and memory efficiency of numerical solvers for the nonequilibrium Dyson equation in the Keldysh formalism. It is based on the empirical observation that the nonequilibrium Green's functions and self energies arising in many problems of physical interest, discretized as matrices, have low rank off-diagonal blocks, and can therefore be compressed using a hierarchical low rank data structure. We describe an efficient algorithm to build this compressed representation on the fly during the course of time stepping, and use the representation to reduce the cost of computing history integrals, which is the main computational bottleneck. For systems with the hierarchical low rank property, our method reduces the computational complexity of solving the nonequilibrium Dyson equation from cubic to near quadratic, and the memory complexity from quadratic to near linear. We demonstrate the full solver for the Falicov-Kimball model exposed to a rapid ramp and Floquet driving of system parameters, and are able to increase feasible propagation times substantially. We present examples with 262144 time steps, which would require approximately five months of computing time and 2.2 TB of memory using the direct time stepping method, but can be completed in just over a day on a laptop with less than 4 GB of memory using our method. We also confirm the hierarchical low rank property for the driven Hubbard model in the weak coupling regime within the GW approximation, and in the strong coupling regime within dynamical mean-field theory. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.06511v3-abstract-full').style.display = 'none'; document.getElementById('2010.06511v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> SciPost Phys. 10, 091 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2007.09749">arXiv:2007.09749</a> <span> [<a href="https://arxiv.org/pdf/2007.09749">pdf</a>, <a href="https://arxiv.org/format/2007.09749">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.125.257601">10.1103/PhysRevLett.125.257601 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Nonlinear spectroscopy of collective modes in excitonic insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Z">Zhiyuan Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Georges%2C+A">Antoine Georges</a>, <a href="/search/cond-mat?searchtype=author&query=Millis%2C+A+J">Andrew J. Millis</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2007.09749v1-abstract-short" style="display: inline;"> The nonlinear optical response of an excitonic insulator coupled to lattice degrees of freedom is shown to depend in strong and characteristic ways on whether the insulating behavior originates primarily from electron-electron or electron-lattice interactions. Linear response optical signatures of the massive phase mode and the amplitude (Higgs) mode are identified. Upon nonlinear excitation reson… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.09749v1-abstract-full').style.display = 'inline'; document.getElementById('2007.09749v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2007.09749v1-abstract-full" style="display: none;"> The nonlinear optical response of an excitonic insulator coupled to lattice degrees of freedom is shown to depend in strong and characteristic ways on whether the insulating behavior originates primarily from electron-electron or electron-lattice interactions. Linear response optical signatures of the massive phase mode and the amplitude (Higgs) mode are identified. Upon nonlinear excitation resonant to the phase mode, a new in-gap mode at twice the phase mode frequency is induced, leading to a huge second harmonic response. Excitation of in-gap phonon modes leads to different and much smaller effects. A Landau-Ginzburg theory analysis explain these different behavior and reveals that a parametric resonance of the strongly excited phase mode is the origin of the photo-induced mode in the electron-dominant case. The difference in the nonlinear optical response serve as a measure of the dominant mechanism of the ordered phase. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.09749v1-abstract-full').style.display = 'none'; document.getElementById('2007.09749v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 July, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 125, 257601 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2007.07801">arXiv:2007.07801</a> <span> [<a href="https://arxiv.org/pdf/2007.07801">pdf</a>, <a href="https://arxiv.org/format/2007.07801">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.102.115157">10.1103/PhysRevB.102.115157 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Comparing the generalized Kadanoff-Baym ansatz with the full Kadanoff-Baym equations for an excitonic insulator out of equilibrium </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Tuovinen%2C+R">Riku Tuovinen</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Sentef%2C+M+A">Michael A. Sentef</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2007.07801v1-abstract-short" style="display: inline;"> We investigate out-of-equilibrium dynamics in an excitonic insulator (EI) with a finite momentum pairing perturbed by a laser-pulse excitation and a sudden coupling to fermionic baths. The transient dynamics of the excitonic order parameter is resolved using the full nonequilibrium Green's function approach and the generalized Kadanoff-Baym ansatz (GKBA) within the second-Born approximation. The c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.07801v1-abstract-full').style.display = 'inline'; document.getElementById('2007.07801v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2007.07801v1-abstract-full" style="display: none;"> We investigate out-of-equilibrium dynamics in an excitonic insulator (EI) with a finite momentum pairing perturbed by a laser-pulse excitation and a sudden coupling to fermionic baths. The transient dynamics of the excitonic order parameter is resolved using the full nonequilibrium Green's function approach and the generalized Kadanoff-Baym ansatz (GKBA) within the second-Born approximation. The comparison between the two approaches after a laser pulse excitation shows a good agreement in the weak and the intermediate photo-doping regime. In contrast, the laser-pulse dynamics resolved by the GKBA does not show a complete melting of the excitonic order after a strong excitation. Instead we observe persistent oscillations of the excitonic order parameter with a predominant frequency given by the renormalized equilibrium bandgap. This anomalous behavior can be overcome within the GKBA formalism by coupling to an external bath, which leads to a transition of the EI system towards the normal state. We analyze the long-time evolution of the system and distinguish decay timescales related to dephasing and thermalization. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.07801v1-abstract-full').style.display = 'none'; document.getElementById('2007.07801v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 July, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 12 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 102, 115157 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2005.11722">arXiv:2005.11722</a> <span> [<a href="https://arxiv.org/pdf/2005.11722">pdf</a>, <a href="https://arxiv.org/ps/2005.11722">ps</a>, <a href="https://arxiv.org/format/2005.11722">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.102.235169">10.1103/PhysRevB.102.235169 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Effects of frustration on the nonequilibrium dynamics of photo-excited lattice systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Bittner%2C+N">Nikolaj Bittner</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2005.11722v1-abstract-short" style="display: inline;"> We theoretically investigate the effects of the lattice geometry on the nonequilibrium dynamics of photo-excited carriers in a half-filled two-dimensional Hubbard model. Using a nonequilibrium generalization of the dynamical cluster approximation, we compare the relaxation dynamics in lattices which interpolate between the triangular lattice and square lattice configuration and thus reveal the rol… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2005.11722v1-abstract-full').style.display = 'inline'; document.getElementById('2005.11722v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2005.11722v1-abstract-full" style="display: none;"> We theoretically investigate the effects of the lattice geometry on the nonequilibrium dynamics of photo-excited carriers in a half-filled two-dimensional Hubbard model. Using a nonequilibrium generalization of the dynamical cluster approximation, we compare the relaxation dynamics in lattices which interpolate between the triangular lattice and square lattice configuration and thus reveal the role of the geometric frustration in these strongly correlated nonequilibrium systems. In particular, we show that the cooling effect resulting from the disordering of the spin background is less effective in the triangular case because of the frustration. This manifests itself in a longer relaxation time of the photo-doped population, as measured by the time-resolved photo-emission signal, and a higher effective temperature of the photo-doped carriers in the non-thermal steady state after the intra-Hubbard-band thermalization. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2005.11722v1-abstract-full').style.display = 'none'; document.getElementById('2005.11722v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 102, 235169 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2003.10799">arXiv:2003.10799</a> <span> [<a href="https://arxiv.org/pdf/2003.10799">pdf</a>, <a href="https://arxiv.org/format/2003.10799">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/sciadv.abd6147">10.1126/sciadv.abd6147 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Imaging the coherent propagation of collective modes in the excitonic insulator candidate Ta$_2$NiSe$_5$ at room temperature </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Bretscher%2C+H+M">Hope M. Bretscher</a>, <a href="/search/cond-mat?searchtype=author&query=Andrich%2C+P">Paolo Andrich</a>, <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Remez%2C+B">Benjamin Remez</a>, <a href="/search/cond-mat?searchtype=author&query=Telang%2C+P">Prachi Telang</a>, <a href="/search/cond-mat?searchtype=author&query=Singh%2C+A">Anupam Singh</a>, <a href="/search/cond-mat?searchtype=author&query=Harnagea%2C+L">Luminita Harnagea</a>, <a href="/search/cond-mat?searchtype=author&query=Cooper%2C+N+R">Nigel R. Cooper</a>, <a href="/search/cond-mat?searchtype=author&query=Millis%2C+A+J">Andrew J. Millis</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Sood%2C+A+K">A. K. Sood</a>, <a href="/search/cond-mat?searchtype=author&query=Rao%2C+A">Akshay Rao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2003.10799v3-abstract-short" style="display: inline;"> Excitonic insulators host a condensate of electron-hole pairs at equilibrium, giving rise to collective many-body effects. Although several materials have emerged as excitonic insulator candidates, evidence of long-range coherence is lacking and the origin of the ordered phase in these systems remains controversial. Here, using ultrafast pump-probe microscopy, we investigate the possible excitonic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.10799v3-abstract-full').style.display = 'inline'; document.getElementById('2003.10799v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2003.10799v3-abstract-full" style="display: none;"> Excitonic insulators host a condensate of electron-hole pairs at equilibrium, giving rise to collective many-body effects. Although several materials have emerged as excitonic insulator candidates, evidence of long-range coherence is lacking and the origin of the ordered phase in these systems remains controversial. Here, using ultrafast pump-probe microscopy, we investigate the possible excitonic insulator Ta$_2$NiSe$_5$. Below 328 K, we observe the anomalous micrometer-scale propagation of coherent modes at velocities of the order of $\sim10^5$ m/s, which we attribute to the hybridization between phonon modes and the phase mode of the condensate. We develop a theoretical framework to support this explanation and propose that electronic interactions provide a significant contribution to the ordered phase in Ta$_2$NiSe$_5$. These results allow us to understand how the condensate's collective modes transport energy and interact with other degrees of freedom. Our study provides a unique paradigm for the investigation and manipulation of these properties in strongly correlated materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.10799v3-abstract-full').style.display = 'none'; document.getElementById('2003.10799v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 March, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science Advances 07 Jul 2021: Science Advances, Vol. 7, no. 28, eabd6147 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2003.10789">arXiv:2003.10789</a> <span> [<a href="https://arxiv.org/pdf/2003.10789">pdf</a>, <a href="https://arxiv.org/format/2003.10789">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.101.195118">10.1103/PhysRevB.101.195118 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Collective Modes in Excitonic Insulators: Effects of Electron-Phonon Coupling and Signatures in Optical Response </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Kaneko%2C+T">Tatsuya Kaneko</a>, <a href="/search/cond-mat?searchtype=author&query=Koga%2C+A">Akihisa Koga</a>, <a href="/search/cond-mat?searchtype=author&query=Millis%2C+A+J">Andrew J. Millis</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2003.10789v2-abstract-short" style="display: inline;"> We consider a two-band spinless model describing an excitonic insulator (EI) on the two-dimensional square lattice with anisotropic hopping parameters and electron-phonon (el-ph) coupling, inspired by the EI candidate Ta$_2$NiSe$_5$. We systematically study the nature of the collective excitations in the ordered phase which originates from the interband Coulomb interaction and the el-ph coupling.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.10789v2-abstract-full').style.display = 'inline'; document.getElementById('2003.10789v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2003.10789v2-abstract-full" style="display: none;"> We consider a two-band spinless model describing an excitonic insulator (EI) on the two-dimensional square lattice with anisotropic hopping parameters and electron-phonon (el-ph) coupling, inspired by the EI candidate Ta$_2$NiSe$_5$. We systematically study the nature of the collective excitations in the ordered phase which originates from the interband Coulomb interaction and the el-ph coupling. When the ordered phase is stabilized only by the Coulomb interaction (pure EI phase), its collective response exhibits a massless phase mode in addition to the amplitude mode. We show that in the BEC regime, the signal of the amplitude mode becomes less prominent and that the anisotropy in the phase mode velocities is relaxed compared to the model bandstructure. Through coupling to the lattice, the phase mode acquires a mass and the signal of the amplitude mode becomes less prominent. Importantly, character of the softening mode at the boundary between the normal semiconductor phase and the ordered phase depends on the parameter condition. In particular, we point out that even for el-ph coupling smaller than the Coulomb interaction the mode that softens to zero at the boundary can have a phonon character. We also discuss how the collective modes can be observed in the optical conductivity. Furthermore, we study the effects of nonlocal interactions on the collective modes and show the possibility of realizing a coexistence of an in-gap mode and an above-gap mode split off from the single amplitude mode in the system with the local interaction only. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.10789v2-abstract-full').style.display = 'none'; document.getElementById('2003.10789v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 March, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 March, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 13 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 101, 195118 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.09726">arXiv:2001.09726</a> <span> [<a href="https://arxiv.org/pdf/2001.09726">pdf</a>, <a href="https://arxiv.org/format/2001.09726">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.101.205140">10.1103/PhysRevB.101.205140 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Electromagnetic coupling in tight-binding models for strongly correlated light and matter </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Li%2C+J">Jiajun Li</a>, <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Mazza%2C+G">Giacomo Mazza</a>, <a href="/search/cond-mat?searchtype=author&query=Millis%2C+A">Andrew Millis</a>, <a href="/search/cond-mat?searchtype=author&query=Georges%2C+A">Antoine Georges</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2001.09726v2-abstract-short" style="display: inline;"> We discuss the construction of low-energy tight-binding Hamiltonians for condensed matter systems with a strong coupling to the quantum electromagnetic field. Such Hamiltonians can be obtained by projecting the continuum theory on a given set of Wannier orbitals. However, different representations of the continuum theory lead to different low-energy formulations, because different representations… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.09726v2-abstract-full').style.display = 'inline'; document.getElementById('2001.09726v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.09726v2-abstract-full" style="display: none;"> We discuss the construction of low-energy tight-binding Hamiltonians for condensed matter systems with a strong coupling to the quantum electromagnetic field. Such Hamiltonians can be obtained by projecting the continuum theory on a given set of Wannier orbitals. However, different representations of the continuum theory lead to different low-energy formulations, because different representations may entangle light and matter, transforming orbitals into light-matter hybrid states before the projection. In particular, a multi-center Power-Zienau-Woolley transformation yields a dipolar Hamiltonian which incorporates the light-matter coupling via both Peierls phases and a polarization density. We compare this dipolar gauge Hamiltonian and the straightforward Coulomb gauge Hamiltonian for a one-dimensional solid, to describe sub-cycle light-driven electronic motion in the semiclassical limit, and a coupling of the solid to a quantized cavity mode which renormalizes the band-structure into electron-polariton bands. Both descriptions yield the same result when many bands are taken into account, but the dipolar Hamiltonian is more accurate when the model is restricted to few electronic bands, while the Coulomb Hamiltonian requires fewer electromagnetic modes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.09726v2-abstract-full').style.display = 'none'; document.getElementById('2001.09726v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 101, 205140 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.00184">arXiv:2001.00184</a> <span> [<a href="https://arxiv.org/pdf/2001.00184">pdf</a>, <a href="https://arxiv.org/format/2001.00184">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1142/S0217984920400540">10.1142/S0217984920400540 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Superconducting optical response of photodoped Mott insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Li%2C+J">Jiajun Li</a>, <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2001.00184v1-abstract-short" style="display: inline;"> Ultrafast laser pulses can redistribute charges in Mott insulators on extremely short time scales, leading to the fast generation of photocarriers. It has recently been demonstrated that these photocarriers can form a novel $畏$--paired condensate at low temperatures, featuring a staggered superconducting pairing field. In this conference paper, we discuss the origin of the $畏$--paired hidden phase… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.00184v1-abstract-full').style.display = 'inline'; document.getElementById('2001.00184v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.00184v1-abstract-full" style="display: none;"> Ultrafast laser pulses can redistribute charges in Mott insulators on extremely short time scales, leading to the fast generation of photocarriers. It has recently been demonstrated that these photocarriers can form a novel $畏$--paired condensate at low temperatures, featuring a staggered superconducting pairing field. In this conference paper, we discuss the origin of the $畏$--paired hidden phase and its optical response which may be detected in a pump-probe experiment. The hidden phase may be relevant for possible light-induced superconductivity in Mott insulators. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.00184v1-abstract-full').style.display = 'none'; document.getElementById('2001.00184v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Conference contribution; presented in the ECSN 2019 in Odessa</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1910.07063">arXiv:1910.07063</a> <span> [<a href="https://arxiv.org/pdf/1910.07063">pdf</a>, <a href="https://arxiv.org/format/1910.07063">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.101.085127">10.1103/PhysRevB.101.085127 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Photo-enhanced excitonic correlations in a Mott insulator with nonlocal interactions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Bittner%2C+N">Nikolaj Bittner</a>, <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1910.07063v1-abstract-short" style="display: inline;"> We investigate the effect of nonlocal interactions on the photo-doped Mott insulating state of the two-dimensional Hubbard model using a nonequilibrium generalization of the dynamical cluster approximation. In particular, we compare the situation where the excitonic states are lying within the continuum of doublon-holon excitations to a set-up where the excitons appear within the Mott gap. In the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.07063v1-abstract-full').style.display = 'inline'; document.getElementById('1910.07063v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1910.07063v1-abstract-full" style="display: none;"> We investigate the effect of nonlocal interactions on the photo-doped Mott insulating state of the two-dimensional Hubbard model using a nonequilibrium generalization of the dynamical cluster approximation. In particular, we compare the situation where the excitonic states are lying within the continuum of doublon-holon excitations to a set-up where the excitons appear within the Mott gap. In the first case, the creation of nearest-neighbor doublon-holon pairs by excitations across the Mott gap results in enhanced excitonic correlations, but these excitons quickly decay into uncorrelated doublons and holons. In the second case, photo-excitation results in long-lived excitonic states. While in a low-temperature equilibrium state, excitonic features are usually not evident in single-particle observables such as the photoemission spectrum, we show that the photo-excited nonequilibrium system can exhibit in-gap states associated with the excitons. The comparison with exact-diagonalization results for small clusters allows us to identify the signatures of the excitons in the photo-emission spectrum. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.07063v1-abstract-full').style.display = 'none'; document.getElementById('1910.07063v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 101, 085127 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1910.04644">arXiv:1910.04644</a> <span> [<a href="https://arxiv.org/pdf/1910.04644">pdf</a>, <a href="https://arxiv.org/format/1910.04644">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevX.10.021062">10.1103/PhysRevX.10.021062 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A unification of the Holstein polaron and dynamic disorder pictures of charge transport in organic semiconductors </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Fetherolf%2C+J+H">Jonathan H. Fetherolf</a>, <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Berkelbach%2C+T+C">Timothy C. Berkelbach</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1910.04644v1-abstract-short" style="display: inline;"> We present a unified and nonperturbative method for calculating spectral and transport properties of Hamiltonians with simultaneous Holstein (diagonal) and Peierls (off-diagonal) electron-phonon coupling. Our approach is motivated by the separation of energy scales in semiconducting organic molecular cystals, in which electrons couple to high-frequency intramolecular Holstein modes and to low-freq… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.04644v1-abstract-full').style.display = 'inline'; document.getElementById('1910.04644v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1910.04644v1-abstract-full" style="display: none;"> We present a unified and nonperturbative method for calculating spectral and transport properties of Hamiltonians with simultaneous Holstein (diagonal) and Peierls (off-diagonal) electron-phonon coupling. Our approach is motivated by the separation of energy scales in semiconducting organic molecular cystals, in which electrons couple to high-frequency intramolecular Holstein modes and to low-frequency intermolecular Peierls modes. We treat Peierls modes as quasi-classical dynamic disorder, while Holstein modes are included with a Lang-Firsov polaron transformation and no narrow-band approximation. Our method reduces to the popular polaron picture due to Holstein coupling and the dynamic disorder picture due to Peierls coupling. We derive an expression for efficient numerical evaluation of the frequency-resolved optical conductivity based on the Kubo formula and obtain the DC mobility from its zero-frequency component. We also use our method to calculate the electron-addition Green's function corresponding to the inverse photoemission spectrum. For realistic parameters, temperature-dependent DC mobility is largely determined by the Peierls-induced dynamic disorder with minor quantitative corrections due to polaronic band-narrowing, and an activated regime is not observed at relevant temperatures. In contrast, for frequency-resolved observables, a quantum mechanical treatment of the Holstein coupling is qualitatively important for capturing the phonon replica satellite structure. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.04644v1-abstract-full').style.display = 'none'; document.getElementById('1910.04644v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 7 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. X 10, 021062 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1909.00828">arXiv:1909.00828</a> <span> [<a href="https://arxiv.org/pdf/1909.00828">pdf</a>, <a href="https://arxiv.org/format/1909.00828">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-020-17925-8">10.1038/s41467-020-17925-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ultrafast coupled charge and spin dynamics in strongly correlated NiO </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Gillmeister%2C+K">Konrad Gillmeister</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Chiang%2C+C">Cheng-Tien Chiang</a>, <a href="/search/cond-mat?searchtype=author&query=Bittner%2C+N">Nikolaj Bittner</a>, <a href="/search/cond-mat?searchtype=author&query=Pavlyukh%2C+Y">Yaroslav Pavlyukh</a>, <a href="/search/cond-mat?searchtype=author&query=Berakdar%2C+J">Jamal Berakdar</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Widdra%2C+W">Wolf Widdra</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1909.00828v1-abstract-short" style="display: inline;"> Charge excitations across an electronic band gap play an important role in opto-electronics and light harvesting. In contrast to conventional semiconductors, studies of above-band-gap photoexcitations in strongly correlated materials are still in their infancy. Here we reveal the ultrafast dynamics controlled by Hund's physics in strongly correlated photo-excited NiO. By combining time-resolved tw… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.00828v1-abstract-full').style.display = 'inline'; document.getElementById('1909.00828v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1909.00828v1-abstract-full" style="display: none;"> Charge excitations across an electronic band gap play an important role in opto-electronics and light harvesting. In contrast to conventional semiconductors, studies of above-band-gap photoexcitations in strongly correlated materials are still in their infancy. Here we reveal the ultrafast dynamics controlled by Hund's physics in strongly correlated photo-excited NiO. By combining time-resolved two-photon photoemission experiments with state-of-the-art numerical calculations, an ultrafast ($\lesssim$ 10\,fs) relaxation due to Hund excitations and related photo-induced in-gap states are identified. Remarkably, the weight of these in-gap states displays long-lived coherent THz oscillations up to 2\,ps at low temperature. The frequency of these oscillations corresponds to the strength of the antiferromagnetic superexchange interaction in NiO and their lifetime vanishes as the N茅el temperature is approached. Numerical simulations of a two-band $t$-$J$ model reveal that the THz oscillations originate from the interplay between local many-body excitations and long-range antiferromagnetic order. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.00828v1-abstract-full').style.display = 'none'; document.getElementById('1909.00828v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2019. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1908.08693">arXiv:1908.08693</a> <span> [<a href="https://arxiv.org/pdf/1908.08693">pdf</a>, <a href="https://arxiv.org/format/1908.08693">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.102.165136">10.1103/PhysRevB.102.165136 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> $畏$--paired superconducting hidden phase in photodoped Mott insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Li%2C+J">Jiajun Li</a>, <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1908.08693v2-abstract-short" style="display: inline;"> We show that a metastable $畏$--pairing superconducting phase can be induced by photodoping doublons and holes into a strongly repulsive fermionic Hubbard model. The doublon-hole condensate originates from an intrinsic doublon-hole exchange interaction and does not rely on the symmetry of the half-filled Hubbard model. It extends over a wide range of doublon densities and effective temperatures. Di… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.08693v2-abstract-full').style.display = 'inline'; document.getElementById('1908.08693v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1908.08693v2-abstract-full" style="display: none;"> We show that a metastable $畏$--pairing superconducting phase can be induced by photodoping doublons and holes into a strongly repulsive fermionic Hubbard model. The doublon-hole condensate originates from an intrinsic doublon-hole exchange interaction and does not rely on the symmetry of the half-filled Hubbard model. It extends over a wide range of doublon densities and effective temperatures. Different non-equilibrium protocols to realize this state are proposed and numerically tested. We also study the optical conductivity in the superconducting phase, which exhibits ideal metallic behavior, i.e., a delta function at zero-frequency in the conductivity, in conjunction with a negative conductivity at large frequencies. These characteristic optical properties can provide a fingerprint of the $畏$-pairing phase in pump-probe experiments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.08693v2-abstract-full').style.display = 'none'; document.getElementById('1908.08693v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 102, 165136 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1908.08515">arXiv:1908.08515</a> <span> [<a href="https://arxiv.org/pdf/1908.08515">pdf</a>, <a href="https://arxiv.org/ps/1908.08515">ps</a>, <a href="https://arxiv.org/format/1908.08515">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.100.155130">10.1103/PhysRevB.100.155130 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Entropy-cooled nonequilibrium states of the Hubbard model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+J">Jiajun Li</a>, <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1908.08515v2-abstract-short" style="display: inline;"> We show that the recently proposed cooling-by-doping mechanism allows to efficiently prepare interesting nonequilibrium states of the Hubbard model. Using nonequilibrium dynamical mean field theory and a particle-hole symmetric setup with dipolar excitations to full and empty bands we produce cold photo-doped Mott insulating states with a sharp Drude peak in the optical conductivity, a superconduc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.08515v2-abstract-full').style.display = 'inline'; document.getElementById('1908.08515v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1908.08515v2-abstract-full" style="display: none;"> We show that the recently proposed cooling-by-doping mechanism allows to efficiently prepare interesting nonequilibrium states of the Hubbard model. Using nonequilibrium dynamical mean field theory and a particle-hole symmetric setup with dipolar excitations to full and empty bands we produce cold photo-doped Mott insulating states with a sharp Drude peak in the optical conductivity, a superconducting state in the repulsive Hubbard model with an inverted population, and $畏$-paired states in systems with a large density of doublons and holons. The reshuffling of entropy into full and empty bands not only provides an efficient cooling mechanism, it also allows to overcome thermalization bottlenecks and slow dynamics that have been observed in systems cooled by the coupling to boson baths. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.08515v2-abstract-full').style.display = 'none'; document.getElementById('1908.08515v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 100, 155130 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1903.08713">arXiv:1903.08713</a> <span> [<a href="https://arxiv.org/pdf/1903.08713">pdf</a>, <a href="https://arxiv.org/format/1903.08713">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.100.235117">10.1103/PhysRevB.100.235117 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multi-band non-equilibrium GW+EDMFT formalism for correlated insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1903.08713v3-abstract-short" style="display: inline;"> We study the dynamics of charge-transfer insulators after a photo-excitation using the three-band Emery model which is relevant for the description of cuprate superconductors. We provide a detailed derivation of the nonequilibrium extension of the multi-band GW+EDMFT formalism and the corresponding downfolding procedure. The Peierls construction of the electron-light coupling is generalized to the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.08713v3-abstract-full').style.display = 'inline'; document.getElementById('1903.08713v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1903.08713v3-abstract-full" style="display: none;"> We study the dynamics of charge-transfer insulators after a photo-excitation using the three-band Emery model which is relevant for the description of cuprate superconductors. We provide a detailed derivation of the nonequilibrium extension of the multi-band GW+EDMFT formalism and the corresponding downfolding procedure. The Peierls construction of the electron-light coupling is generalized to the multi-band case resulting in a gauge invariant combination of the Peierls intra-band acceleration and dipolar intra-band transitions. We apply the formalism to the study of momentum-dependent (inverse) photo-emission spectra and optical conductivities. The time-resolved spectral function shows a strong renormalization of the charge-transfer gap and a substantial broadening of some of the bands. While the upper Hubbard band exhibits a momentum-dependent broadening, an almost rigid band shift is observed for the ligand bands. The inverse photo-emission spectrum reveals that the inclusion of the non-local and inter-band charge fluctuations lead to a very fast relaxation of holes into the lower Hubbard band. Consistent with the changes in the spectral function, the optical conductivity shows a renormalization of the charge-transfer gap, which is proportional to the photo-doping. The details of the photo-induced changes strongly depend on the dipolar matrix elements, which calls for an ab-initio determination of these parameters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.08713v3-abstract-full').style.display = 'none'; document.getElementById('1903.08713v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 March, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Substantial updates on a discussion of light-matter coupling and corrected results for optical conductivity</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 100, 235117 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1810.01598">arXiv:1810.01598</a> <span> [<a href="https://arxiv.org/pdf/1810.01598">pdf</a>, <a href="https://arxiv.org/format/1810.01598">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.99.045118">10.1103/PhysRevB.99.045118 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A comparative study of nonequilibrium insulator-to-metal transitions in electron-phonon systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Sayyad%2C+S">Sharareh Sayyad</a>, <a href="/search/cond-mat?searchtype=author&query=Zitko%2C+R">Rok Zitko</a>, <a href="/search/cond-mat?searchtype=author&query=Strand%2C+H+U+R">Hugo U. R. Strand</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1810.01598v1-abstract-short" style="display: inline;"> We study equilibrium and nonequilibrium properties of electron-phonon systems described by the Hubbard-Holstein model using the dynamical mean-field theory. In equilibrium, we benchmark the results for impurity solvers based on the one-crossing approximation and slave-rotor approximation against non-perturbative numerical renormalization group reference data. We also examine how well the low energ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.01598v1-abstract-full').style.display = 'inline'; document.getElementById('1810.01598v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1810.01598v1-abstract-full" style="display: none;"> We study equilibrium and nonequilibrium properties of electron-phonon systems described by the Hubbard-Holstein model using the dynamical mean-field theory. In equilibrium, we benchmark the results for impurity solvers based on the one-crossing approximation and slave-rotor approximation against non-perturbative numerical renormalization group reference data. We also examine how well the low energy properties of the electron-boson coupled systems can be reproduced by an effective static electron-electron interaction. The one-crossing and slave-rotor approximations are then used to simulate insulator-to-metal transitions induced by a sudden switch-on of the electron-phonon interaction. The slave-rotor results suggest the existence of a critical electron-phonon coupling above which the system is transiently trapped in a non-thermal metallic state with coherent quasiparticles. The same quench protocol in the one-crossing approximation results in a bad metallic state. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.01598v1-abstract-full').style.display = 'none'; document.getElementById('1810.01598v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 October, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 19 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 99, 045118 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1808.02264">arXiv:1808.02264</a> <span> [<a href="https://arxiv.org/pdf/1808.02264">pdf</a>, <a href="https://arxiv.org/format/1808.02264">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.100.041111">10.1103/PhysRevB.100.041111 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dynamics of photo-doped charge transfer insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Boehnke%2C+L">Lewin Boehnke</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1808.02264v1-abstract-short" style="display: inline;"> We study the dynamics of charge-transfer insulators after photo-excitation using the three-band Emery model and a nonequilibrium extension of Hartree-Fock+EDMFT and GW+EDMFT. While the equilibrium properties are accurately reproduced by the Hartree-Fock treatment of the full $p$ bands, dynamical correlations are essential for a proper description of the photo-doped state. The insertion of doublons… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.02264v1-abstract-full').style.display = 'inline'; document.getElementById('1808.02264v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1808.02264v1-abstract-full" style="display: none;"> We study the dynamics of charge-transfer insulators after photo-excitation using the three-band Emery model and a nonequilibrium extension of Hartree-Fock+EDMFT and GW+EDMFT. While the equilibrium properties are accurately reproduced by the Hartree-Fock treatment of the full $p$ bands, dynamical correlations are essential for a proper description of the photo-doped state. The insertion of doublons and holons leads to a renormalization of the charge transfer gap %and $p$ bands and to a substantial broadening of the bands. We calculate the time-resolved photoemission spectrum and optical conductivity and find qualitative agreement with experiments. Our formalism enables the realistic description of nonequilibrium phenomena in a large class of charge-transfer insulators, and provides a tool to explore the optical manipulation of interaction and correlation effects. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.02264v1-abstract-full').style.display = 'none'; document.getElementById('1808.02264v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 100, 041111 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1808.00712">arXiv:1808.00712</a> <span> [<a href="https://arxiv.org/pdf/1808.00712">pdf</a>, <a href="https://arxiv.org/format/1808.00712">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1002/pssb.201800469">10.1002/pssb.201800469 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Adiabatic Preparation of a Correlated Symmetry-Broken Initial State with the Generalized Kadanoff--Baym Ansatz </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Tuovinen%2C+R">Riku Tuovinen</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Sch%C3%BCler%2C+M">Michael Sch眉ler</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Sentef%2C+M+A">Michael A. Sentef</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1808.00712v2-abstract-short" style="display: inline;"> A fast time propagation method for nonequilibrium Green's functions based on the generalized Kadanoff--Baym Ansatz (GKBA) is applied to a lattice system with a symmetry-broken equilibrium phase, namely an excitonic insulator. The adiabatic preparation of a correlated symmetry-broken initial state from a Hartree--Fock wave function within GKBA is assessed by comparing with a solution of the imagina… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.00712v2-abstract-full').style.display = 'inline'; document.getElementById('1808.00712v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1808.00712v2-abstract-full" style="display: none;"> A fast time propagation method for nonequilibrium Green's functions based on the generalized Kadanoff--Baym Ansatz (GKBA) is applied to a lattice system with a symmetry-broken equilibrium phase, namely an excitonic insulator. The adiabatic preparation of a correlated symmetry-broken initial state from a Hartree--Fock wave function within GKBA is assessed by comparing with a solution of the imaginary-time Dyson equation. We find that it is possible to reach a symmetry-broken correlated initial state with nonzero excitonic order parameter by the adiabatic switching procedure. We discuss under which circumstances this is possible in practice within reasonably short switching times. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.00712v2-abstract-full').style.display = 'none'; document.getElementById('1808.00712v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 5 figures, Progress in Nonequilibrium Green's Functions VII proceedings</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1803.02071">arXiv:1803.02071</a> <span> [<a href="https://arxiv.org/pdf/1803.02071">pdf</a>, <a href="https://arxiv.org/ps/1803.02071">ps</a>, <a href="https://arxiv.org/format/1803.02071">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.97.235125">10.1103/PhysRevB.97.235125 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Coupled charge and spin dynamics in a photo-excited Mott insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Bittner%2C+N">Nikolaj Bittner</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Strand%2C+H+U+R">Hugo U. R. Strand</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1803.02071v1-abstract-short" style="display: inline;"> Using a nonequilibrium implementation of the extended dynamical mean field theory (EDMFT) we simulate the relaxation after photo excitation in a strongly correlated electron system with antiferromagnetic spin interactions. We consider the $t$-$J$ model and focus on the interplay between the charge- and spin-dynamics in different excitation and doping regimes. The appearance of string states after… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1803.02071v1-abstract-full').style.display = 'inline'; document.getElementById('1803.02071v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1803.02071v1-abstract-full" style="display: none;"> Using a nonequilibrium implementation of the extended dynamical mean field theory (EDMFT) we simulate the relaxation after photo excitation in a strongly correlated electron system with antiferromagnetic spin interactions. We consider the $t$-$J$ model and focus on the interplay between the charge- and spin-dynamics in different excitation and doping regimes. The appearance of string states after a weak photo excitation manifests itself in a nontrivial scaling of the relaxation time with the exchange coupling and leads to a correlated oscillatory evolution of the kinetic energy and spin-spin correlation function. A strong excitation of the system, on the other hand, suppresses the spin correlations and results in a relaxation that is controlled by hole scattering. We discuss the possibility of detecting string states in optical and cold atom experiments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1803.02071v1-abstract-full').style.display = 'none'; document.getElementById('1803.02071v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 March, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 97, 235125 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1707.07706">arXiv:1707.07706</a> <span> [<a href="https://arxiv.org/pdf/1707.07706">pdf</a>, <a href="https://arxiv.org/format/1707.07706">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.119.247601">10.1103/PhysRevLett.119.247601 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Photo-induced enhancement of excitonic order </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Murakami%2C+Y">Yuta Murakami</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1707.07706v1-abstract-short" style="display: inline;"> We study the dynamics of excitonic insulators coupled to phonons. Without phonon couplings, the linear response is given by the damped amplitude oscillations of the order parameter with frequency equal to the minimum band gap. A phonon coupling to the interband transfer integral induces two types of long-lived collective oscillations of the amplitude, one originating from the phonon dynamics and t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.07706v1-abstract-full').style.display = 'inline'; document.getElementById('1707.07706v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1707.07706v1-abstract-full" style="display: none;"> We study the dynamics of excitonic insulators coupled to phonons. Without phonon couplings, the linear response is given by the damped amplitude oscillations of the order parameter with frequency equal to the minimum band gap. A phonon coupling to the interband transfer integral induces two types of long-lived collective oscillations of the amplitude, one originating from the phonon dynamics and the other from the phase mode, which becomes massive. We show that even for small phonon coupling, a photo-induced enhancement of the exciton condensation and the gap can be realized. Using the Anderson pseudo-spin picture, we argue that the origin of the enhancement is a cooperative effect of the massive phase mode and the Hartree shift induced by the photo excitation. We also discuss how the enhancement of the order and the collective modes can be observed with time-resolved photo-emission spectroscopy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.07706v1-abstract-full').style.display = 'none'; document.getElementById('1707.07706v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 July, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5pages, 4 figures + 8 pages, 8 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 119, 247601 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1704.06101">arXiv:1704.06101</a> <span> [<a href="https://arxiv.org/pdf/1704.06101">pdf</a>, <a href="https://arxiv.org/format/1704.06101">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.96.165104">10.1103/PhysRevB.96.165104 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Hund's coupling driven photo-carrier relaxation in the two-band Mott insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Strand%2C+H+U+R">Hugo U. R. Strand</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1704.06101v1-abstract-short" style="display: inline;"> We study the relaxation dynamics of photo-carriers in the paramagnetic Mott insulating phase of the half-filled two-band Hubbard model. Using nonequilibrium dynamical mean field theory, we excite charge carriers across the Mott gap by a short hopping modulation, and simulate the evolution of the photo-doped population within the Hubbard bands. We observe an ultrafast charge-carrier relaxation driv… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.06101v1-abstract-full').style.display = 'inline'; document.getElementById('1704.06101v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1704.06101v1-abstract-full" style="display: none;"> We study the relaxation dynamics of photo-carriers in the paramagnetic Mott insulating phase of the half-filled two-band Hubbard model. Using nonequilibrium dynamical mean field theory, we excite charge carriers across the Mott gap by a short hopping modulation, and simulate the evolution of the photo-doped population within the Hubbard bands. We observe an ultrafast charge-carrier relaxation driven by emission of local spin excitations with an inverse relaxation time proportional to the Hund's coupling. The photo-doping generates additional side-bands in the spectral function, and for strong Hund's coupling, the photo-doped population also splits into several resonances. The dynamics of the local many-body states reveals two effects, thermal blocking and kinetic freezing, which manifest themselves when the Hund's coupling becomes of the order of the temperature or the bandwidth, respectively. These effects, which are absent in the single-band Hubbard model, should be relevant for the interpretation of experiments on correlated materials with multiple active orbitals. In particular, the features revealed in the non-equilibrium energy distribution of the photo-carriers are experimentally accessible, and provide information on the role of the Hund's coupling in these materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.06101v1-abstract-full').style.display = 'none'; document.getElementById('1704.06101v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 April, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 11 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 96, 165104 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1702.05300">arXiv:1702.05300</a> <span> [<a href="https://arxiv.org/pdf/1702.05300">pdf</a>, <a href="https://arxiv.org/format/1702.05300">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.120.166401">10.1103/PhysRevLett.120.166401 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ultrafast doublon dynamics in photo-excited 1T-TaS$_2$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ligges%2C+M">Manuel Ligges</a>, <a href="/search/cond-mat?searchtype=author&query=Avigo%2C+I">Isabella Avigo</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Strand%2C+H">Hugo Strand</a>, <a href="/search/cond-mat?searchtype=author&query=Stojchevska%2C+L">Ljupka Stojchevska</a>, <a href="/search/cond-mat?searchtype=author&query=Kall%C3%A4ne%2C+M">Matthias Kall盲ne</a>, <a href="/search/cond-mat?searchtype=author&query=Zhou%2C+P">Ping Zhou</a>, <a href="/search/cond-mat?searchtype=author&query=Rossnagel%2C+K">Kai Rossnagel</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Bovensiepen%2C+U">Uwe Bovensiepen</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1702.05300v2-abstract-short" style="display: inline;"> Strongly correlated systems exhibit intriguing properties caused by intertwined microscopic in- teractions that are hard to disentangle in equilibrium. Employing non-equilibrium time-resolved photoemission spectroscopy on the quasi-two-dimensional transition-metal dichalcogenide 1T-TaS$_2$, we identify a spectroscopic signature of double occupied sites (doublons) that are reflects fundamental Mott… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.05300v2-abstract-full').style.display = 'inline'; document.getElementById('1702.05300v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1702.05300v2-abstract-full" style="display: none;"> Strongly correlated systems exhibit intriguing properties caused by intertwined microscopic in- teractions that are hard to disentangle in equilibrium. Employing non-equilibrium time-resolved photoemission spectroscopy on the quasi-two-dimensional transition-metal dichalcogenide 1T-TaS$_2$, we identify a spectroscopic signature of double occupied sites (doublons) that are reflects fundamental Mott physics. Doublon-hole recombination is estimated to occur on time scales of one electronic hopping cycle $\hbar/J\approx$ 14 fs. Despite strong electron-phonon coupling the dynamics can be explained by purely electronic effects captured by the single band Hubbard model, where thermalization is fast in the small-gap regime. Qualitative agreement with the experimental results however requires the assumption of an intrinsic hole-doping. The sensitivity of the doublon dynamics on the doping level provides a way to control ultrafast processes in such strongly correlated materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.05300v2-abstract-full').style.display = 'none'; document.getElementById('1702.05300v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 June, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 February, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 120, 166401 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1702.04952">arXiv:1702.04952</a> <span> [<a href="https://arxiv.org/pdf/1702.04952">pdf</a>, <a href="https://arxiv.org/format/1702.04952">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.118.246402">10.1103/PhysRevLett.118.246402 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Nonequilibrium GW+EDMFT: Antiscreening and inverted populations from nonlocal correlations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Boehnke%2C+L">Lewin Boehnke</a>, <a href="/search/cond-mat?searchtype=author&query=Strand%2C+H">Hugo Strand</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1702.04952v2-abstract-short" style="display: inline;"> We study the dynamics of screening in photo-doped Mott insulators with long-ranged interactions using a nonequilibrium implementation of the $GW$ plus extended dynamical mean field theory ($GW$+EDMFT) formalism. Our study demonstrates that the complex interplay of the injected carriers with bosonic degrees of freedom (charge fluctuations) can result in long-lived transient states with properties t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.04952v2-abstract-full').style.display = 'inline'; document.getElementById('1702.04952v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1702.04952v2-abstract-full" style="display: none;"> We study the dynamics of screening in photo-doped Mott insulators with long-ranged interactions using a nonequilibrium implementation of the $GW$ plus extended dynamical mean field theory ($GW$+EDMFT) formalism. Our study demonstrates that the complex interplay of the injected carriers with bosonic degrees of freedom (charge fluctuations) can result in long-lived transient states with properties that are distinctly different from those of thermal equilibrium states. Systems with strong nonlocal interactions are found to exhibit a self-sustained population inversion of the doublons and holes. This population inversion leads to low-energy antiscreening which can be detected in time-resolved electron-energy loss spectra. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.04952v2-abstract-full').style.display = 'none'; document.getElementById('1702.04952v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 April, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 February, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 118, 246402 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1608.05586">arXiv:1608.05586</a> <span> [<a href="https://arxiv.org/pdf/1608.05586">pdf</a>, <a href="https://arxiv.org/ps/1608.05586">ps</a>, <a href="https://arxiv.org/format/1608.05586">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.119.086401">10.1103/PhysRevLett.119.086401 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ultrafast Electronic Band Gap Control in an Excitonic Insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Mor%2C+S">Selene Mor</a>, <a href="/search/cond-mat?searchtype=author&query=Herzog%2C+M">Marc Herzog</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Katayama%2C+N">Naoyuki Katayama</a>, <a href="/search/cond-mat?searchtype=author&query=Nohara%2C+M">Minoru Nohara</a>, <a href="/search/cond-mat?searchtype=author&query=Takagi%2C+H">Hide Takagi</a>, <a href="/search/cond-mat?searchtype=author&query=Mizokawa%2C+T">Takashi Mizokawa</a>, <a href="/search/cond-mat?searchtype=author&query=Monney%2C+C">Claude Monney</a>, <a href="/search/cond-mat?searchtype=author&query=St%C3%A4hler%2C+J">Julia St盲hler</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1608.05586v2-abstract-short" style="display: inline;"> We report on the nonequilibrium dynamics of the electronic structure of the layered semiconductor Ta$_2$NiSe$_5$ investigated by time- and angle-resolved photoelectron spectroscopy. We show that below the critical excitation density of $F_{C} = 0.2$ mJ cm$^{-2}$, the band gap $narrows$ transiently, while it is $enhanced$ above $F_{C}$. Hartree-Fock calculations reveal that this effect can be expla… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.05586v2-abstract-full').style.display = 'inline'; document.getElementById('1608.05586v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1608.05586v2-abstract-full" style="display: none;"> We report on the nonequilibrium dynamics of the electronic structure of the layered semiconductor Ta$_2$NiSe$_5$ investigated by time- and angle-resolved photoelectron spectroscopy. We show that below the critical excitation density of $F_{C} = 0.2$ mJ cm$^{-2}$, the band gap $narrows$ transiently, while it is $enhanced$ above $F_{C}$. Hartree-Fock calculations reveal that this effect can be explained by the presence of the low-temperature excitonic insulator phase of Ta$_2$NiSe$_5$, whose order parameter is connected to the gap size. This work demonstrates the ability to manipulate the band gap of Ta$_2$NiSe$_5$ with light on the femtosecond time scale. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.05586v2-abstract-full').style.display = 'none'; document.getElementById('1608.05586v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 August, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 119, 086401 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1604.03784">arXiv:1604.03784</a> <span> [<a href="https://arxiv.org/pdf/1604.03784">pdf</a>, <a href="https://arxiv.org/format/1604.03784">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.94.035121">10.1103/PhysRevB.94.035121 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Photo-induced gap closure in an excitonic insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1604.03784v1-abstract-short" style="display: inline;"> We study the dynamical phase transition out of an excitonic insulator phase after photo-excitation using a time-dependent extension of the selfconsistent GW method. We connect the evolution of the photoemission spectra to the dynamics of the excitonic order parameter and identify two dynamical phase transition points marked by a slowdown in the relaxation: one critical point is connected with the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.03784v1-abstract-full').style.display = 'inline'; document.getElementById('1604.03784v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1604.03784v1-abstract-full" style="display: none;"> We study the dynamical phase transition out of an excitonic insulator phase after photo-excitation using a time-dependent extension of the selfconsistent GW method. We connect the evolution of the photoemission spectra to the dynamics of the excitonic order parameter and identify two dynamical phase transition points marked by a slowdown in the relaxation: one critical point is connected with the trapping in a nonthermal state with reduced exciton density and the second corresponds to the thermal phase transition. The transfer of kinetic energy from the photoexcited carriers to the exciton condensate is shown to be the main mechanism for the gap melting. We analyze the low energy dynamics of screening, which strongly depends on the presence of the excitonic gap, and argue that it is difficult to interpret the static component of the screened interaction as the effective interaction of some low energy model. Instead we propose a phenomenological measure for the effective interaction which indicates that screening has minor effects on the low energy dynamics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.03784v1-abstract-full').style.display = 'none'; document.getElementById('1604.03784v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 April, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 94, 035121 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1507.07953">arXiv:1507.07953</a> <span> [<a href="https://arxiv.org/pdf/1507.07953">pdf</a>, <a href="https://arxiv.org/format/1507.07953">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.92.195123">10.1103/PhysRevB.92.195123 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dynamics of screening in photo-doped Mott insulators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Eckstein%2C+M">Martin Eckstein</a>, <a href="/search/cond-mat?searchtype=author&query=Werner%2C+P">Philipp Werner</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1507.07953v1-abstract-short" style="display: inline;"> We use a nonequilibrium implementation of extended dynamical mean field theory to study the effect of dynamical screening in photo-excited Mott insulators. The insertion of doublons and holes adds low-energy screening modes and leads to a reduction of the Mott gap. The coupling to low-energy bosonic modes further- more opens new relaxation channels and significantly speeds up the thermalization pr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1507.07953v1-abstract-full').style.display = 'inline'; document.getElementById('1507.07953v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1507.07953v1-abstract-full" style="display: none;"> We use a nonequilibrium implementation of extended dynamical mean field theory to study the effect of dynamical screening in photo-excited Mott insulators. The insertion of doublons and holes adds low-energy screening modes and leads to a reduction of the Mott gap. The coupling to low-energy bosonic modes further- more opens new relaxation channels and significantly speeds up the thermalization process. We also consider the effect of the energy distribution of the doped carriers on the screening. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1507.07953v1-abstract-full').style.display = 'none'; document.getElementById('1507.07953v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 July, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PRB92, 195123(2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1501.03833">arXiv:1501.03833</a> <span> [<a href="https://arxiv.org/pdf/1501.03833">pdf</a>, <a href="https://arxiv.org/format/1501.03833">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nphys3265">10.1038/nphys3265 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Snapshots of the retarded interaction of charge carriers with ultrafast fluctuations in cuprates </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Conte%2C+S+D">S. Dal Conte</a>, <a href="/search/cond-mat?searchtype=author&query=Vidmar%2C+L">L. Vidmar</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">D. Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Mierzejewski%2C+M">M. Mierzejewski</a>, <a href="/search/cond-mat?searchtype=author&query=Soavi%2C+G">G. Soavi</a>, <a href="/search/cond-mat?searchtype=author&query=Peli%2C+S">S. Peli</a>, <a href="/search/cond-mat?searchtype=author&query=Banfi%2C+F">F. Banfi</a>, <a href="/search/cond-mat?searchtype=author&query=Ferrini%2C+G">G. Ferrini</a>, <a href="/search/cond-mat?searchtype=author&query=Comin%2C+R">R. Comin</a>, <a href="/search/cond-mat?searchtype=author&query=Ludbrook%2C+B+M">B. M. Ludbrook</a>, <a href="/search/cond-mat?searchtype=author&query=Chauviere%2C+L">L. Chauviere</a>, <a href="/search/cond-mat?searchtype=author&query=Zhigadlo%2C+N+D">N. D. Zhigadlo</a>, <a href="/search/cond-mat?searchtype=author&query=Eisaki%2C+H">H. Eisaki</a>, <a href="/search/cond-mat?searchtype=author&query=Greven%2C+M">M. Greven</a>, <a href="/search/cond-mat?searchtype=author&query=Lupi%2C+S">S. Lupi</a>, <a href="/search/cond-mat?searchtype=author&query=Damascelli%2C+A">A. Damascelli</a>, <a href="/search/cond-mat?searchtype=author&query=Brida%2C+D">D. Brida</a>, <a href="/search/cond-mat?searchtype=author&query=Capone%2C+M">M. Capone</a>, <a href="/search/cond-mat?searchtype=author&query=Bon%C4%8Da%2C+J">J. Bon膷a</a>, <a href="/search/cond-mat?searchtype=author&query=Cerullo%2C+G">G. Cerullo</a>, <a href="/search/cond-mat?searchtype=author&query=Giannetti%2C+C">C. Giannetti</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1501.03833v1-abstract-short" style="display: inline;"> One of the pivotal questions in the physics of high-temperature superconductors is whether the low-energy dynamics of the charge carriers is mediated by bosons with a characteristic timescale. This issue has remained elusive since electronic correlations are expected to dramatically speed up the electron-boson scattering processes, confining them to the very femtosecond timescale that is hard to a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.03833v1-abstract-full').style.display = 'inline'; document.getElementById('1501.03833v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1501.03833v1-abstract-full" style="display: none;"> One of the pivotal questions in the physics of high-temperature superconductors is whether the low-energy dynamics of the charge carriers is mediated by bosons with a characteristic timescale. This issue has remained elusive since electronic correlations are expected to dramatically speed up the electron-boson scattering processes, confining them to the very femtosecond timescale that is hard to access even with state-of-the-art ultrafast techniques. Here we simultaneously push the time resolution and the frequency range of transient reflectivity measurements up to an unprecedented level that enables us to directly observe the 16 fs build-up of the effective electron-boson interaction in hole-doped copper oxides. This extremely fast timescale is in agreement with numerical calculations based on the t-J model and the repulsive Hubbard model, in which the relaxation of the photo-excited charges is achieved via inelastic scattering with short-range antiferromagnetic excitations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.03833v1-abstract-full').style.display = 'none'; document.getElementById('1501.03833v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 January, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">to appear in Nature Physics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Physics 11, 421-426 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1402.6104">arXiv:1402.6104</a> <span> [<a href="https://arxiv.org/pdf/1402.6104">pdf</a>, <a href="https://arxiv.org/format/1402.6104">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.90.125104">10.1103/PhysRevB.90.125104 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Unusual Two-stage Dynamics of the Spin-Lattice Polaron Formation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kogoj%2C+J">Jan Kogoj</a>, <a href="/search/cond-mat?searchtype=author&query=Lenarcic%2C+Z">Zala Lenarcic</a>, <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">Denis Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Mierzejewski%2C+M">Marcin Mierzejewski</a>, <a href="/search/cond-mat?searchtype=author&query=Prelovsek%2C+P">Peter Prelovsek</a>, <a href="/search/cond-mat?searchtype=author&query=Bonca%2C+J">Janez Bonca</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1402.6104v1-abstract-short" style="display: inline;"> We follow the formation of a spin-lattice polaron after a quantum quench that simulates absorption of the pump{pulse in the time-resolved experiments. We discover a two-stage relaxation where spin and lattice degrees of freedom represent an integral part of the relaxation mechanism. In the first stage the kinetic energy of the spin-lattice polaron relaxes towards its ground state value while relax… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1402.6104v1-abstract-full').style.display = 'inline'; document.getElementById('1402.6104v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1402.6104v1-abstract-full" style="display: none;"> We follow the formation of a spin-lattice polaron after a quantum quench that simulates absorption of the pump{pulse in the time-resolved experiments. We discover a two-stage relaxation where spin and lattice degrees of freedom represent an integral part of the relaxation mechanism. In the first stage the kinetic energy of the spin-lattice polaron relaxes towards its ground state value while relaxation processes via spin and phonon degrees of freedom remain roughly independent. In the second, typically much longer stage, a subsequent energy transfer between lattice and spin degrees of freedom via the charge carrier emerges. The excess local spin energy radiates away via magnon excitations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1402.6104v1-abstract-full').style.display = 'none'; document.getElementById('1402.6104v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 February, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 90, 125104 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1312.1962">arXiv:1312.1962</a> <span> [<a href="https://arxiv.org/pdf/1312.1962">pdf</a>, <a href="https://arxiv.org/format/1312.1962">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.89.125123">10.1103/PhysRevB.89.125123 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optical response of highly excited particles in a strongly correlated system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lenar%C4%8Di%C4%8D%2C+Z">Zala Lenar膷i膷</a>, <a href="/search/cond-mat?searchtype=author&query=Gole%C5%BE%2C+D">Denis Gole啪</a>, <a href="/search/cond-mat?searchtype=author&query=Bon%C4%8Da%2C+J">Janez Bon膷a</a>, <a href="/search/cond-mat?searchtype=author&query=Prelov%C5%A1ek%2C+P">Peter Prelov拧ek</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1312.1962v3-abstract-short" style="display: inline;"> We present a linear-response formalism for a system of correlated electrons out of equilibrium, as relevant for the probe optical absorption in pump-probe experiments. We consider the time dependent optical conductivity $蟽(蠅,t)$ and its nonequilibrium properties. As an application we numerically study a single highly excited charged particle in the spin background, as described within the two-dime… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1312.1962v3-abstract-full').style.display = 'inline'; document.getElementById('1312.1962v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1312.1962v3-abstract-full" style="display: none;"> We present a linear-response formalism for a system of correlated electrons out of equilibrium, as relevant for the probe optical absorption in pump-probe experiments. We consider the time dependent optical conductivity $蟽(蠅,t)$ and its nonequilibrium properties. As an application we numerically study a single highly excited charged particle in the spin background, as described within the two-dimensional $t$-$J$ model. Our results show that the optical sum rule approaches the equilibrium-like one very fast, however, the time evolution and the final asymptotic behavior of the absorption spectra in the finite systems considered still reveal dependence on the type of initial pump perturbation. This is observed in the evolution of its main features: the mid-infrared peak and the Drude weight. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1312.1962v3-abstract-full').style.display = 'none'; document.getElementById('1312.1962v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 April, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 December, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 89, 125123 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1311.5574">arXiv:1311.5574</a> <span> [<a href="https://arxiv.org/pdf/1311.5574">pdf</a>, <a href="https://arxiv.org/format/1311.5574">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.89.165118">10.1103/PhysRevB.89.165118 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Mechanism of Ultrafast Relaxation of a Photo-Carrier in Antiferromagnetic Spin Background </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Golez%2C+D">D. Golez</a>, <a href="/search/cond-mat?searchtype=author&query=Bonca%2C+J">J. Bonca</a>, <a href="/search/cond-mat?searchtype=author&query=Mierzejewski%2C+M">M. Mierzejewski</a>, <a href="/search/cond-mat?searchtype=author&query=Vidmar%2C+L">L. Vidmar</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1311.5574v2-abstract-short" style="display: inline;"> We study the relaxation mechanism of a highly excited carrier propagating in the antiferromagnetic background modeled by the $t$-$J$ Hamiltonian on a square lattice. We show that the relaxation consists of two distinct stages. The initial ultrafast stage with the relaxation time $蟿\sim (\hbar/t_0)(J/t_0)^{-2/3}$ (where $t_0$ is the hopping integral and $J$ is the exchange interaction) is based on… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1311.5574v2-abstract-full').style.display = 'inline'; document.getElementById('1311.5574v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1311.5574v2-abstract-full" style="display: none;"> We study the relaxation mechanism of a highly excited carrier propagating in the antiferromagnetic background modeled by the $t$-$J$ Hamiltonian on a square lattice. We show that the relaxation consists of two distinct stages. The initial ultrafast stage with the relaxation time $蟿\sim (\hbar/t_0)(J/t_0)^{-2/3}$ (where $t_0$ is the hopping integral and $J$ is the exchange interaction) is based on generation of string states in the close proximity of the carrier. This unusual scaling of $蟿$ is obtained by means of comparison of numerical results with a simplified $t$-$J_z$ model on a Bethe lattice. In the subsequent (much slower) stage local spin excitations are carried away by magnons. The relaxation time on the two-leg ladder system is an order of magnitude longer due to the lack of string excitations. This further reinforces the importance of string excitations for the ultrafast relaxation in the two-dimensional system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1311.5574v2-abstract-full').style.display = 'none'; document.getElementById('1311.5574v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 May, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 November, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 89, 165118 (2014) </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Golez%2C+D&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Golez%2C+D&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Golez%2C+D&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul 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