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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=Wang%2C+A&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Wang%2C+A&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Wang%2C+A&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/2408.07342">arXiv:2408.07342</a> <span> [<a href="https://arxiv.org/pdf/2408.07342">pdf</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="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</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"> Evidence of P-wave Pairing in K2Cr3As3 Superconductors from Phase-sensitive Measurement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Z">Zhiyuan Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Dou%2C+Z">Ziwei Dou</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Anqi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+C">Cuiwei Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Hong%2C+Y">Yu Hong</a>, <a href="/search/quant-ph?searchtype=author&query=Lei%2C+X">Xincheng Lei</a>, <a href="/search/quant-ph?searchtype=author&query=Pan%2C+Y">Yue Pan</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Z">Zhongchen Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+Z">Zhipeng Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yupeng Li</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+G">Guoan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+X">Xiaofan Shi</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+X">Xingchen Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+X">Xiao Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Lyu%2C+Z">Zhaozheng Lyu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+P">Peiling Li</a>, <a href="/search/quant-ph?searchtype=author&query=Qu%2C+F">Faming Qu</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+G">Guangtong Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+D">Dong Su</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+K">Kun Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Shi%2C+Y">Youguo Shi</a>, <a href="/search/quant-ph?searchtype=author&query=Lu%2C+L">Li Lu</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+J">Jie Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+J">Jiangping Hu</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="2408.07342v1-abstract-short" style="display: inline;"> P-wave superconductors hold immense promise for both fundamental physics and practical applications due to their unusual pairing symmetry and potential topological superconductivity. However, the exploration of the p-wave superconductors has proved to be a complex endeavor. Not only are they rare in nature but also the identification of p-wave superconductors has been an arduous task in history. F… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.07342v1-abstract-full').style.display = 'inline'; document.getElementById('2408.07342v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.07342v1-abstract-full" style="display: none;"> P-wave superconductors hold immense promise for both fundamental physics and practical applications due to their unusual pairing symmetry and potential topological superconductivity. However, the exploration of the p-wave superconductors has proved to be a complex endeavor. Not only are they rare in nature but also the identification of p-wave superconductors has been an arduous task in history. For example, phase-sensitive measurement, an experimental technique which can provide conclusive evidence for unconventional pairing, has not been implemented successfully to identify p-wave superconductors. Here, we study a recently discovered family of superconductors, A2Cr3As3 (A = K, Rb, Cs), which were proposed theoretically to be a candidate of p-wave superconductors. We fabricate superconducting quantum interference devices (SQUIDs) on exfoliated K2Cr3As3, and perform the phase-sensitive measurement. We observe that such SQUIDs exhibit a pronounced second-order harmonic component sin(2蠁) in the current-phase relation, suggesting the admixture of 0- and 蟺-phase. By carefully examining the magnetic field dependence of the oscillation patterns of critical current and Shapiro steps under microwave irradiation, we reveal a crossover from 0- to 蟺-dominating phase state and conclude that the existence of the 蟺-phase is in favor of the p-wave pairing symmetry in K2Cr3As3. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.07342v1-abstract-full').style.display = 'none'; document.getElementById('2408.07342v1-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> 14 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.08680">arXiv:2405.08680</a> <span> [<a href="https://arxiv.org/pdf/2405.08680">pdf</a>, <a href="https://arxiv.org/format/2405.08680">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</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"> Generalized uncertainty principle distorted quintessence dynamics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bhandari%2C+G">Gaurav Bhandari</a>, <a href="/search/quant-ph?searchtype=author&query=Pathak%2C+S+D">S. D. Pathak</a>, <a href="/search/quant-ph?searchtype=author&query=Sharma%2C+M">Manabendra Sharma</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Anzhong Wang</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="2405.08680v1-abstract-short" style="display: inline;"> In this paper, we invoke a generalized uncertainty principle (GUP) in the symmetry-reduced cosmological Hamiltonian for a universe driven by a quintessence scalar field with potential. Our study focuses on semi-classical regime. In particular, we derive the GUP-distorted Friedmann, Raychaudhuri, and the Klein-Gordon equation. This is followed by a systematic analysis of the qualitative dynamics fo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.08680v1-abstract-full').style.display = 'inline'; document.getElementById('2405.08680v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.08680v1-abstract-full" style="display: none;"> In this paper, we invoke a generalized uncertainty principle (GUP) in the symmetry-reduced cosmological Hamiltonian for a universe driven by a quintessence scalar field with potential. Our study focuses on semi-classical regime. In particular, we derive the GUP-distorted Friedmann, Raychaudhuri, and the Klein-Gordon equation. This is followed by a systematic analysis of the qualitative dynamics for the choice of potential $V(蠁)= V_0 \sinh^{-n}{(渭蠁)}$. This involves constructing an autonomous dynamical system of equations by choosing appropriate dynamical variables, followed by a qualitative study using linear stability theory. Our analysis shows that incorporating GUP significantly changes the existing fixed points compared to the limiting case without quantum effects by switching off the GUP. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.08680v1-abstract-full').style.display = 'none'; document.getElementById('2405.08680v1-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> 14 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">12. arXiv admin note: text overlap with arXiv:2404.09049</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.02100">arXiv:2402.02100</a> <span> [<a href="https://arxiv.org/pdf/2402.02100">pdf</a>, <a href="https://arxiv.org/ps/2402.02100">ps</a>, <a href="https://arxiv.org/format/2402.02100">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</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/10.1103/PhysRevA.109.L060601">10.1103/PhysRevA.109.L060601 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Weak-measurement-based pseudospin pointer: A cost-effective scheme for precision measurement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ye%2C+L">Ling Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Luo%2C+L">Lan Luo</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">An Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Ge%2C+R">Rongchun Ge</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Z">Zhiyou Zhang</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="2402.02100v2-abstract-short" style="display: inline;"> As an essential component of state-of-the-art quantum technologies, fast and efficient quantum measurements are in persistent demand over time. We present a proof-of-principle experiment on a new dimensionless pseudo-spin pointer based on weak measurement. In the context of optical parameter estimation, we demonstrate that the parametric distribution's moment is obtained experimentally by employin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.02100v2-abstract-full').style.display = 'inline'; document.getElementById('2402.02100v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.02100v2-abstract-full" style="display: none;"> As an essential component of state-of-the-art quantum technologies, fast and efficient quantum measurements are in persistent demand over time. We present a proof-of-principle experiment on a new dimensionless pseudo-spin pointer based on weak measurement. In the context of optical parameter estimation, we demonstrate that the parametric distribution's moment is obtained experimentally by employing the dimensionless pointer without measuring the distribution literally. In addition to the sheer liberation of experimental expense, the photon-countering-based pointer is well-calibrated for the detection of weak signals. We show that for signals $3$-$4$ orders of weaker in strength than the area-array camera method, an order of improvement in precision is achieved experimentally. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.02100v2-abstract-full').style.display = 'none'; document.getElementById('2402.02100v2-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 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">6 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 109, L060601 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.01947">arXiv:2312.01947</a> <span> [<a href="https://arxiv.org/pdf/2312.01947">pdf</a>, <a href="https://arxiv.org/format/2312.01947">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Machine Learning">cs.LG</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/PhysRevResearch.6.023098">10.1103/PhysRevResearch.6.023098 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Maximising Quantum-Computing Expressive Power through Randomised Circuits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Yang%2C+Y">Yingli Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Z">Zongkang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Anbang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+X">Xiaosi Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+X">Xiaoting Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Ying Li</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="2312.01947v1-abstract-short" style="display: inline;"> In the noisy intermediate-scale quantum era, variational quantum algorithms (VQAs) have emerged as a promising avenue to obtain quantum advantage. However, the success of VQAs depends on the expressive power of parameterised quantum circuits, which is constrained by the limited gate number and the presence of barren plateaus. In this work, we propose and numerically demonstrate a novel approach fo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.01947v1-abstract-full').style.display = 'inline'; document.getElementById('2312.01947v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.01947v1-abstract-full" style="display: none;"> In the noisy intermediate-scale quantum era, variational quantum algorithms (VQAs) have emerged as a promising avenue to obtain quantum advantage. However, the success of VQAs depends on the expressive power of parameterised quantum circuits, which is constrained by the limited gate number and the presence of barren plateaus. In this work, we propose and numerically demonstrate a novel approach for VQAs, utilizing randomised quantum circuits to generate the variational wavefunction. We parameterize the distribution function of these random circuits using artificial neural networks and optimize it to find the solution. This random-circuit approach presents a trade-off between the expressive power of the variational wavefunction and time cost, in terms of the sampling cost of quantum circuits. Given a fixed gate number, we can systematically increase the expressive power by extending the quantum-computing time. With a sufficiently large permissible time cost, the variational wavefunction can approximate any quantum state with arbitrary accuracy. Furthermore, we establish explicit relationships between expressive power, time cost, and gate number for variational quantum eigensolvers. These results highlight the promising potential of the random-circuit approach in achieving a high expressive power in quantum computing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.01947v1-abstract-full').style.display = 'none'; document.getElementById('2312.01947v1-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> 4 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">19 pages, 10 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Research 6, 023098(2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.17927">arXiv:2310.17927</a> <span> [<a href="https://arxiv.org/pdf/2310.17927">pdf</a>, <a href="https://arxiv.org/format/2310.17927">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> A Pure Quantum Approximate Optimization Algorithm Based on CNR Operation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Lv%2C+D+Y">Da You Lv</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="2310.17927v6-abstract-short" style="display: inline;"> By introducing the "comparison and replacement" (CNR) operation, we propose a general-purpose pure quantum approximate optimization algorithm and derive its core optimization mechanism quantitatively. The algorithm is constructed to a $p$-level divide-and-conquer structure based on the CNR operations. The quality of approximate optimization improves with the increase of $p$. For sufficiently gener… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.17927v6-abstract-full').style.display = 'inline'; document.getElementById('2310.17927v6-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.17927v6-abstract-full" style="display: none;"> By introducing the "comparison and replacement" (CNR) operation, we propose a general-purpose pure quantum approximate optimization algorithm and derive its core optimization mechanism quantitatively. The algorithm is constructed to a $p$-level divide-and-conquer structure based on the CNR operations. The quality of approximate optimization improves with the increase of $p$. For sufficiently general optimization problems, the algorithm can work and produce the near-optimal solutions as expected with considerably high probability. Moreover, we demonstrate that the algorithm is scalable to be applied to large size problems. Our algorithm is applied to two optimization problems with significantly different degeneracy, the Gaussian weighted 2-edge graph and MAX-2-XOR, and then we show the algorithm performance in detail when the required qubits number of the two optimization problems is 10. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.17927v6-abstract-full').style.display = 'none'; document.getElementById('2310.17927v6-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 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.13419">arXiv:2310.13419</a> <span> [<a href="https://arxiv.org/pdf/2310.13419">pdf</a>, <a href="https://arxiv.org/format/2310.13419">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> Low Cross-Talk Optical Addressing of Trapped-Ion Qubits Using a Novel Integrated Photonic Chip </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Sotirova%2C+A+S">A. S. Sotirova</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+B">B. Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Leppard%2C+J+D">J. D. Leppard</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">A. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+M">M. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Vazquez-Brennan%2C+A">A. Vazquez-Brennan</a>, <a href="/search/quant-ph?searchtype=author&query=Nadlinger%2C+D+P">D. P. Nadlinger</a>, <a href="/search/quant-ph?searchtype=author&query=Moser%2C+S">S. Moser</a>, <a href="/search/quant-ph?searchtype=author&query=Jesacher%2C+A">A. Jesacher</a>, <a href="/search/quant-ph?searchtype=author&query=He%2C+C">C. He</a>, <a href="/search/quant-ph?searchtype=author&query=Pokorny%2C+F">F. Pokorny</a>, <a href="/search/quant-ph?searchtype=author&query=Booth%2C+M+J">M. J. Booth</a>, <a href="/search/quant-ph?searchtype=author&query=Ballance%2C+C+J">C. J. Ballance</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="2310.13419v1-abstract-short" style="display: inline;"> Individual optical addressing in chains of trapped atomic ions requires generation of many small, closely spaced beams with low cross-talk. Furthermore, implementing parallel operations necessitates phase, frequency, and amplitude control of each individual beam. Here we present a scalable method for achieving all of these capabilities using a novel integrated photonic chip coupled to a network of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.13419v1-abstract-full').style.display = 'inline'; document.getElementById('2310.13419v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.13419v1-abstract-full" style="display: none;"> Individual optical addressing in chains of trapped atomic ions requires generation of many small, closely spaced beams with low cross-talk. Furthermore, implementing parallel operations necessitates phase, frequency, and amplitude control of each individual beam. Here we present a scalable method for achieving all of these capabilities using a novel integrated photonic chip coupled to a network of optical fibre components. The chip design results in very low cross-talk between neighbouring channels even at the micrometre-scale spacing by implementing a very high refractive index contrast between the channel core and cladding. Furthermore, the photonic chip manufacturing procedure is highly flexible, allowing for the creation of devices with an arbitrary number of channels as well as non-uniform channel spacing at the chip output. We present the system used to integrate the chip within our ion trap apparatus and characterise the performance of the full individual addressing setup using a single trapped ion as a light-field sensor. Our measurements showed intensity cross-talk below $10^{-3}$ across the chip, with minimum observed cross-talk as low as $O\left(10^{-5}\right)$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.13419v1-abstract-full').style.display = 'none'; document.getElementById('2310.13419v1-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 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">14 pages, 12 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/2304.03551">arXiv:2304.03551</a> <span> [<a href="https://arxiv.org/pdf/2304.03551">pdf</a>, <a href="https://arxiv.org/format/2304.03551">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</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"> Femtosecond laser induced creation of G and W-centers in silicon-on-insulator substrates </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Quard%2C+H">Hugo Quard</a>, <a href="/search/quant-ph?searchtype=author&query=Khoury%2C+M">Mario Khoury</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Andong Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Herzig%2C+T">Tobias Herzig</a>, <a href="/search/quant-ph?searchtype=author&query=Meijer%2C+J">Jan Meijer</a>, <a href="/search/quant-ph?searchtype=author&query=Pezzagna%2C+S">Sebastian Pezzagna</a>, <a href="/search/quant-ph?searchtype=author&query=Cueff%2C+S">S茅bastien Cueff</a>, <a href="/search/quant-ph?searchtype=author&query=Grojo%2C+D">David Grojo</a>, <a href="/search/quant-ph?searchtype=author&query=Abbarchi%2C+M">Marco Abbarchi</a>, <a href="/search/quant-ph?searchtype=author&query=Nguyen%2C+H+S">Hai Son Nguyen</a>, <a href="/search/quant-ph?searchtype=author&query=Chauvin%2C+N">Nicolas Chauvin</a>, <a href="/search/quant-ph?searchtype=author&query=Wood%2C+T">Thomas Wood</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="2304.03551v1-abstract-short" style="display: inline;"> The creation of fluorescent defects in silicon is a key stepping stone towards assuring the integration perspectives of quantum photonic devices into existing technologies. Here we demonstrate the creation, by femtosecond laser annealing, of W and G-centers in commercial silicon on insulator (SOI) previously implanted with 12C+ ions. Their quality is comparable to that found for the same emitters… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.03551v1-abstract-full').style.display = 'inline'; document.getElementById('2304.03551v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.03551v1-abstract-full" style="display: none;"> The creation of fluorescent defects in silicon is a key stepping stone towards assuring the integration perspectives of quantum photonic devices into existing technologies. Here we demonstrate the creation, by femtosecond laser annealing, of W and G-centers in commercial silicon on insulator (SOI) previously implanted with 12C+ ions. Their quality is comparable to that found for the same emitters obtained with conventional implant processes; as quantified by the photoluminescence radiative lifetime, the broadening of their zero-phonon line (ZPL) and the evolution of these quantities with temperature. In addition to this, we show that both defects can be created without carbon implantation and that we can erase the G-centers by annealing while enhancing the W-centers' emission. These demonstrations are relevant to the deterministic and operando generation of quantum emitters in silicon. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.03551v1-abstract-full').style.display = 'none'; document.getElementById('2304.03551v1-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 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">8 pages, 4 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/2301.13353">arXiv:2301.13353</a> <span> [<a href="https://arxiv.org/pdf/2301.13353">pdf</a>, <a href="https://arxiv.org/format/2301.13353">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.22331/q-2024-08-13-1438">10.22331/q-2024-08-13-1438 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Measurement-efficient quantum Krylov subspace diagonalisation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Z">Zongkang Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Anbang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+X">Xiaosi Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Ying Li</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="2301.13353v3-abstract-short" style="display: inline;"> The Krylov subspace methods, being one category of the most important classical numerical methods for linear algebra problems, can be much more powerful when generalised to quantum computing. However, quantum Krylov subspace algorithms are prone to errors due to inevitable statistical fluctuations in quantum measurements. To address this problem, we develop a general theoretical framework to analy… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.13353v3-abstract-full').style.display = 'inline'; document.getElementById('2301.13353v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.13353v3-abstract-full" style="display: none;"> The Krylov subspace methods, being one category of the most important classical numerical methods for linear algebra problems, can be much more powerful when generalised to quantum computing. However, quantum Krylov subspace algorithms are prone to errors due to inevitable statistical fluctuations in quantum measurements. To address this problem, we develop a general theoretical framework to analyse the statistical error and measurement cost. Based on the framework, we propose a quantum algorithm to construct the Hamiltonian-power Krylov subspace that can minimise the measurement cost. In our algorithm, the product of power and Gaussian functions of the Hamiltonian is expressed as an integral of the real-time evolution, such that it can be evaluated on a quantum computer. We compare our algorithm with other established quantum Krylov subspace algorithms in solving two prominent examples. To achieve an error comparable to that of the classical Lanczos algorithm at the same subspace dimension, our algorithm typically requires orders of magnitude fewer measurements than others. Such an improvement can be attributed to the reduced cost of composing projectors onto the ground state. These results show that our algorithm is exceptionally robust to statistical fluctuations and promising for practical applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.13353v3-abstract-full').style.display = 'none'; document.getElementById('2301.13353v3-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 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">29 pages, 9 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Quantum 8, 1438 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2212.09020">arXiv:2212.09020</a> <span> [<a href="https://arxiv.org/pdf/2212.09020">pdf</a>, <a href="https://arxiv.org/format/2212.09020">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> An Extension of Many-Interacting-Worlds Method on Non-Guassian Model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+W">Wen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="2212.09020v3-abstract-short" style="display: inline;"> Discussions about whether quantum theory is determinism or indeterminism has lasted for a century. A new approach to standard quantum mechanics called many-interacting-worlds method based on many-worlds interpretation and de Broglie-Bohm mechanics provided the possibility to demonstrate probability from deterministic universe.The many-interacting-worlds method has been proved successful in the gro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.09020v3-abstract-full').style.display = 'inline'; document.getElementById('2212.09020v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2212.09020v3-abstract-full" style="display: none;"> Discussions about whether quantum theory is determinism or indeterminism has lasted for a century. A new approach to standard quantum mechanics called many-interacting-worlds method based on many-worlds interpretation and de Broglie-Bohm mechanics provided the possibility to demonstrate probability from deterministic universe.The many-interacting-worlds method has been proved successful in the ground state of harmonic oscillator. In this article we extend this method to one dimensional Coulomb potential and construct a corresponding empirical density function. We also provide a theoretical proof of the convergence of density function. Our numerical simulation of one dimensional Coulomb potential in the first excited state obtains the consistent result with standard quantum mechanics and shows the applicability of many-interacting-worlds method. This research provides the possibility to extend many-interacting-worlds method to non-Gaussian quantum systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.09020v3-abstract-full').style.display = 'none'; document.getElementById('2212.09020v3-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 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2208.10562">arXiv:2208.10562</a> <span> [<a href="https://arxiv.org/pdf/2208.10562">pdf</a>, <a href="https://arxiv.org/format/2208.10562">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-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/10.3390/">10.3390/ <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </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/universe8100543">universe8100543 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dirac observables in the 4-dimensional phase space of Ashtekar's variables and spherically symmetric loop quantum black holes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ongole%2C+G">Geeth Ongole</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+H">Hongchao Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+T">Tao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Anzhong Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+B">Bin Wang</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="2208.10562v2-abstract-short" style="display: inline;"> In this paper, we study a proposal put forward recently by Bodendorfer, Mele and M眉nch and Garc\'谋a-Quismondo and Marug谩n, in which the two polymerization parameters of spherically symmetric black hole spacetimes are the Dirac observables of the four-dimensional Ashtekar's variables. In this model, black and white hole horizons in general exist and naturally divide the spacetime into the external… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.10562v2-abstract-full').style.display = 'inline'; document.getElementById('2208.10562v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.10562v2-abstract-full" style="display: none;"> In this paper, we study a proposal put forward recently by Bodendorfer, Mele and M眉nch and Garc\'谋a-Quismondo and Marug谩n, in which the two polymerization parameters of spherically symmetric black hole spacetimes are the Dirac observables of the four-dimensional Ashtekar's variables. In this model, black and white hole horizons in general exist and naturally divide the spacetime into the external and internal regions. In the external region, the spacetime can be made asymptotically flat by properly choosing the dependence of the two polymerization parameters on the Ashtekar variables. Then, we find that the asymptotical behavior of the spacetime is universal, and, to the leading order, the curvature invariants are independent of the mass parameter $m$. For example, the Kretschmann scalar approaches zero as $K \simeq A_0r^{-4}$ asymptotically, where $A_0$ is generally a non-zero constant and independent of $m$, and $r$ the geometric radius of the two-spheres. In the internal region, all the physical quantities are finite, and the Schwarzschild black hole singularity is replaced by a transition surface whose radius is always finite and non-zero. The quantum gravitational effects are negligible near the black hole horizon for very massive black holes. However, the behavior of the spacetime across the transition surface is significantly different from all loop quantum black holes studied so far. In particular, the location of the maximum amplitude of the curvature scalars is displaced from the transition surface and depends on $m$, so does the maximum amplitude. In addition, the radius of the white hole is much smaller than that of the black hole, and its exact value sensitively depends on $m$, too. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.10562v2-abstract-full').style.display = 'none'; document.getElementById('2208.10562v2-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 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2022. </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">revetex4-1, 2 tables and 13 figures. To appear in Universe for the Special Issue "Loop Quantum Gravity: A Themed Issue in Honor of Prof. Abhay Ashtekar"</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Universe 8 (2022) 543 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2208.06800">arXiv:2208.06800</a> <span> [<a href="https://arxiv.org/pdf/2208.06800">pdf</a>, <a href="https://arxiv.org/ps/2208.06800">ps</a>, <a href="https://arxiv.org/format/2208.06800">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1016/j.rinp.2023.106575">10.1016/j.rinp.2023.106575 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum metrology with quantum Wheatstone bridge composed of Bose systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Yao%2C+X">Xiwei Yao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="2208.06800v1-abstract-short" style="display: inline;"> The quantum version of a special classical Wheatstone bridge built with a boundary-driven spin system has recently been proposed. We propose a quantum Wheatstone bridge consisting of Bose systems, which can simulate the general classical Wheatstone bridge. Unknown coupling can be obtained when the quantum Wheatstone bridge is balanced, which can be determined simply by the homodyne detection. When… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.06800v1-abstract-full').style.display = 'inline'; document.getElementById('2208.06800v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.06800v1-abstract-full" style="display: none;"> The quantum version of a special classical Wheatstone bridge built with a boundary-driven spin system has recently been proposed. We propose a quantum Wheatstone bridge consisting of Bose systems, which can simulate the general classical Wheatstone bridge. Unknown coupling can be obtained when the quantum Wheatstone bridge is balanced, which can be determined simply by the homodyne detection. When the expectation value of the homodyne detection is 0, the quantum Wheatstone bridge is unbalanced. Regulate a known coupling strength to make the expectation value of the homodyne detection be proportional to the square root of the initial number of bosons, which means that the quantum Wheatstone bridge is balanced. By calculating the quantum Fisher information, we show that the measurement precision is optimal when the quantum Wheatstone bridge is balanced. And the homodyne detection is close to the optimal measurement in the case of low-temperature baths. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.06800v1-abstract-full').style.display = 'none'; document.getElementById('2208.06800v1-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> 14 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2022. </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">8pages, 3figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Results in Physics, 50, 106575 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2208.05808">arXiv:2208.05808</a> <span> [<a href="https://arxiv.org/pdf/2208.05808">pdf</a>, <a href="https://arxiv.org/ps/2208.05808">ps</a>, <a href="https://arxiv.org/format/2208.05808">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</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/PhysRevA.106.023518">10.1103/PhysRevA.106.023518 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A general scheme of differential imaging employing weak measurement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liu%2C+X">Xiong Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">An Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+J">Junfan Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Ye%2C+L">Ling Ye</a>, <a href="/search/quant-ph?searchtype=author&query=Ge%2C+R">Rongchun Ge</a>, <a href="/search/quant-ph?searchtype=author&query=Du%2C+J">Jinglei Du</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+H">Hong Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Z">Zhiyou Zhang</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="2208.05808v1-abstract-short" style="display: inline;"> We propose and experimentally realize a general scheme of differential imaging employing the idea of weak measurement. We show that the weak coupling between the system of interest and a two-level ancilla can introduce a two-beam circuit after an arbitrary pre-selection of the ancilla. By choosing the post-selection orthogonal to the pre-selection measurement, an effective imaging platform based o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.05808v1-abstract-full').style.display = 'inline'; document.getElementById('2208.05808v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.05808v1-abstract-full" style="display: none;"> We propose and experimentally realize a general scheme of differential imaging employing the idea of weak measurement. We show that the weak coupling between the system of interest and a two-level ancilla can introduce a two-beam circuit after an arbitrary pre-selection of the ancilla. By choosing the post-selection orthogonal to the pre-selection measurement, an effective imaging platform based on differential operations is shown achieved. Experimental results on both the Sagnac interferometer and ultra-thin Wollaston prism demonstrate that our imaging scheme successfully yields the boundary information of complex geometric configurations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.05808v1-abstract-full').style.display = 'none'; document.getElementById('2208.05808v1-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 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2022. </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">11 figures, accepted for publication in Phys. Rev. A</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.05577">arXiv:2204.05577</a> <span> [<a href="https://arxiv.org/pdf/2204.05577">pdf</a>, <a href="https://arxiv.org/ps/2204.05577">ps</a>, <a href="https://arxiv.org/format/2204.05577">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1016/j.rinp.2022.105957">10.1016/j.rinp.2022.105957 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum estimation of Kerr nonlinearity in driven-dissipative systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="2204.05577v1-abstract-short" style="display: inline;"> We mainly investigate the quantum measurement of Kerr nonlinearity in the driven-dissipative system. Without the dissipation, the measurement precision of the nonlinearity parameter $蠂$ scales as "super-Heisenberg scaling" $1/N^2$ with $N$ being the total average number of particles (photons) due to the nonlinear generator. Here, we find that "super-Heisenberg scaling" $1/N^{3/2}$ can also be obta… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.05577v1-abstract-full').style.display = 'inline'; document.getElementById('2204.05577v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.05577v1-abstract-full" style="display: none;"> We mainly investigate the quantum measurement of Kerr nonlinearity in the driven-dissipative system. Without the dissipation, the measurement precision of the nonlinearity parameter $蠂$ scales as "super-Heisenberg scaling" $1/N^2$ with $N$ being the total average number of particles (photons) due to the nonlinear generator. Here, we find that "super-Heisenberg scaling" $1/N^{3/2}$ can also be obtained by choosing a proper interrogation time. In the steady state, the "super-Heisenberg scaling" $1/N^{3/2}$ can only be achieved when the nonlinearity parameter is close to 0 in the case of the single-photon loss and the one-photon driving or the two-photon driving. The "super-Heisenberg scaling" disappears with the increase of the strength of the nonlinearity. When the system suffers from the two-photon loss in addition to the single-photon loss, the optimal measurement precision will not appear at the nonlinearity $蠂=0$ in the case of the one-photon driving. Counterintuitively, in the case of the two-photon driving we find that it is not the case that the higher the two-photon loss, the lower the measurement precision. It means that the measurement precision of $蠂$ can be improved to some extent by increasing the two-photon loss. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.05577v1-abstract-full').style.display = 'none'; document.getElementById('2204.05577v1-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 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">Comments:</span> <span class="has-text-grey-dark mathjax">8pages,5figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Results in Physics, 42, 105957 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2203.13466">arXiv:2203.13466</a> <span> [<a href="https://arxiv.org/pdf/2203.13466">pdf</a>, <a href="https://arxiv.org/ps/2203.13466">ps</a>, <a href="https://arxiv.org/format/2203.13466">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/PhysRevA.106.052407">10.1103/PhysRevA.106.052407 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum thermometry in diffraction-limited systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="2203.13466v1-abstract-short" style="display: inline;"> We investigate the ultimate quantum limit of resolving the temperatures of two thermal sources affected by the diffraction. More quantum Fisher information can be obtained with the priori information than that without the priori information. We carefully consider two strategies: the simultaneous estimation and the individual estimation. The simultaneous estimation of two temperatures is proved to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.13466v1-abstract-full').style.display = 'inline'; document.getElementById('2203.13466v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2203.13466v1-abstract-full" style="display: none;"> We investigate the ultimate quantum limit of resolving the temperatures of two thermal sources affected by the diffraction. More quantum Fisher information can be obtained with the priori information than that without the priori information. We carefully consider two strategies: the simultaneous estimation and the individual estimation. The simultaneous estimation of two temperatures is proved to satisfy the saturation condition of quantum Cram茅r bound and performs better than the individual estimation in the case of small degree of diffraction given the same resources. However, in the case of high degree of diffraction, the individual estimation performs better. In particular, at the maximum diffraction, the simultaneous estimation can not get any information, which is supported by a practical measurement, while the individual estimation can still get the information. In addition, we find that for the individual estimation, a practical and feasible estimation strategy by using the full Hermite-Gauss basis can saturate the quantum Cram茅r bound without being affected by the attenuation factor at the maximum diffraction. using the full Hermite-Gauss basis can saturate the quantum Cram茅r bound without being affected by the attenuation factor at the maximum diffraction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.13466v1-abstract-full').style.display = 'none'; document.getElementById('2203.13466v1-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, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2022. </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">9pages, 8figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 106, 052407 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2111.09622">arXiv:2111.09622</a> <span> [<a href="https://arxiv.org/pdf/2111.09622">pdf</a>, <a href="https://arxiv.org/format/2111.09622">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/PhysRevResearch.4.043140">10.1103/PhysRevResearch.4.043140 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Error-mitigated deep-circuit quantum simulation of open systems: steady state and relaxation rate problems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Anbang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+J">Jingning Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Ying Li</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="2111.09622v3-abstract-short" style="display: inline;"> Deep-circuit quantum computation, like Shor's algorithm, is undermined by error accumulation, and near-future quantum techniques are far from adequate for full-fledged quantum error correction. Instead of resorting to shallow-circuit quantum algorithms, recent theoretical research suggests that digital quantum simulation (DQS) of closed quantum systems are robust against the accumulation of Trotte… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.09622v3-abstract-full').style.display = 'inline'; document.getElementById('2111.09622v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.09622v3-abstract-full" style="display: none;"> Deep-circuit quantum computation, like Shor's algorithm, is undermined by error accumulation, and near-future quantum techniques are far from adequate for full-fledged quantum error correction. Instead of resorting to shallow-circuit quantum algorithms, recent theoretical research suggests that digital quantum simulation (DQS) of closed quantum systems are robust against the accumulation of Trotter errors, as long as local observables are concerned. In this paper, we investigate digital quantum simulation of open quantum systems. First, we prove that the deviation in the steady state obtained from digital quantum simulation depends only on the error in a single Trotter step, which indicates that error accumulation may not be disastrous. By numerical simulation of the quantum circuits for the DQS of the dissipative XYZ model, we then show that the correct results can be recovered by quantum error mitigation as long as the error rate in the DQS is below a sharp threshold. We explain this threshold behavior by the existence of a dissipation-driven quantum phase transition. Finally, we propose a new error-mitigation technique based on the scaling behavior in the vicinity of the critical point of a quantum phase transition. Our results expand the territory of near-future available quantum algorithms and stimulate further theoretical and experimental efforts in practical quantum applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.09622v3-abstract-full').style.display = 'none'; document.getElementById('2111.09622v3-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 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.06553">arXiv:2109.06553</a> <span> [<a href="https://arxiv.org/pdf/2109.06553">pdf</a>, <a href="https://arxiv.org/ps/2109.06553">ps</a>, <a href="https://arxiv.org/format/2109.06553">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/PhysRevA.104.062418">10.1103/PhysRevA.104.062418 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum phases transition revealed by the exceptional point in Hopfield-Bogoliubov matrix </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="2109.06553v1-abstract-short" style="display: inline;"> We use the exceptional point in Hopfield-Bogoliubov matrix to find the phase transition points in the bosonic system. In many previous jobs, the excitation energy vanished at the critical point. It can be stated equivalently that quantum critical point is obtained when the determinant of Hopfield-Bogoliubov matrix vanishes. We analytically obtain the Hopfield-Bogoliubov matrix corresponding to the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.06553v1-abstract-full').style.display = 'inline'; document.getElementById('2109.06553v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.06553v1-abstract-full" style="display: none;"> We use the exceptional point in Hopfield-Bogoliubov matrix to find the phase transition points in the bosonic system. In many previous jobs, the excitation energy vanished at the critical point. It can be stated equivalently that quantum critical point is obtained when the determinant of Hopfield-Bogoliubov matrix vanishes. We analytically obtain the Hopfield-Bogoliubov matrix corresponding to the general quadratic Hamiltonian. For single-mode system the appearance of the exceptional point in Hopfield-Bogoliubov matrix is equivalent to the disappearance of the determinant of Hopfield-Bogoliubov matrix. However, in multi-mode bosonic system, they are not equivalent except in some special cases. For example, in the case of perfect symmetry, that is, swapping any two subsystems and keeping the total Hamiltonian invariable, the exceptional point and the degenerate point coincide all the time when the phase transition occurs. When the exceptional point and the degenerate point do not coincide, we find a significant result. With the increase of two-photon driving intensity, the normal phase changes to the superradiant phase, then the superradiant phase changes to the normal phase, and finally the normal phase changes to the superradiant phase. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.06553v1-abstract-full').style.display = 'none'; document.getElementById('2109.06553v1-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> 14 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">7pages,4figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 104,062418 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2105.12906">arXiv:2105.12906</a> <span> [<a href="https://arxiv.org/pdf/2105.12906">pdf</a>, <a href="https://arxiv.org/ps/2105.12906">ps</a>, <a href="https://arxiv.org/format/2105.12906">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1140/epjp/s13360-022-03524-7">10.1140/epjp/s13360-022-03524-7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum Thermometry with a Dissipative Quantum Rabi System </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="2105.12906v1-abstract-short" style="display: inline;"> Dissipative quantum Rabi System, a finite-component system composed of a single two-level atom interacting with an optical cavity field mode, exhibits a quantum phase transition, which can be exploited to greatly enhance the estimation precision of unitary parameters (frequency and coupling strength). Here, using the quantum Langevin equation, standard mean field theory and adiabatic elimination,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.12906v1-abstract-full').style.display = 'inline'; document.getElementById('2105.12906v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2105.12906v1-abstract-full" style="display: none;"> Dissipative quantum Rabi System, a finite-component system composed of a single two-level atom interacting with an optical cavity field mode, exhibits a quantum phase transition, which can be exploited to greatly enhance the estimation precision of unitary parameters (frequency and coupling strength). Here, using the quantum Langevin equation, standard mean field theory and adiabatic elimination, we investigate the quantum thermometry of a thermal bath surrounding the atom with quantum optical probes. With the increase of coupling strength between the atom and the cavity field, two kinds of singularities can be observed. One type of singularity is the exceptional point (EP) in the anti-parity-time (anti-$\mathcal{PT}$) symmetrical cavity field. The other type of singularity is the critical point (CP) of phase transition from the normal to superradiant phase. We show that the optimal measurement precision occurs at the CP, instead of the EP. And the direct photon detection represents an excellent proxy for the optimal measurement near the CP. In the case where the thermal bath to be tested is independent of the extra thermal bath interacting with the cavity field, the estimation precision of the temperature always increases with the coupling strength. Oppositely, if the thermal bath to be tested is in equilibrium with the extra bath interacting with the cavity field, noises that suppress the information of the temperature will be introduced when increasing the coupling strength unless it is close to the CP. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.12906v1-abstract-full').style.display = 'none'; document.getElementById('2105.12906v1-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 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">10pages,5figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Eur. Phys. J. Plus 137:1323 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2104.05059">arXiv:2104.05059</a> <span> [<a href="https://arxiv.org/pdf/2104.05059">pdf</a>, <a href="https://arxiv.org/format/2104.05059">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</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/PhysRevResearch.3.033221">10.1103/PhysRevResearch.3.033221 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Application of Quantum Machine Learning using the Quantum Kernel Algorithm on High Energy Physics Analysis at the LHC </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wu%2C+S+L">Sau Lan Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+S">Shaojun Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+W">Wen Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+C">Chen Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Chan%2C+J">Jay Chan</a>, <a href="/search/quant-ph?searchtype=author&query=Cheng%2C+C+L">Chi Lung Cheng</a>, <a href="/search/quant-ph?searchtype=author&query=Pham%2C+T">Tuan Pham</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+Y">Yan Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+Z">Alex Zeng Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+R">Rui Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Livny%2C+M">Miron Livny</a>, <a href="/search/quant-ph?searchtype=author&query=Glick%2C+J">Jennifer Glick</a>, <a href="/search/quant-ph?searchtype=author&query=Barkoutsos%2C+P+K">Panagiotis Kl. Barkoutsos</a>, <a href="/search/quant-ph?searchtype=author&query=Woerner%2C+S">Stefan Woerner</a>, <a href="/search/quant-ph?searchtype=author&query=Tavernelli%2C+I">Ivano Tavernelli</a>, <a href="/search/quant-ph?searchtype=author&query=Carminati%2C+F">Federico Carminati</a>, <a href="/search/quant-ph?searchtype=author&query=Di+Meglio%2C+A">Alberto Di Meglio</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+A+C+Y">Andy C. Y. Li</a>, <a href="/search/quant-ph?searchtype=author&query=Lykken%2C+J">Joseph Lykken</a>, <a href="/search/quant-ph?searchtype=author&query=Spentzouris%2C+P">Panagiotis Spentzouris</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+S+Y">Samuel Yen-Chi Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Yoo%2C+S">Shinjae Yoo</a>, <a href="/search/quant-ph?searchtype=author&query=Wei%2C+T">Tzu-Chieh Wei</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="2104.05059v2-abstract-short" style="display: inline;"> Quantum machine learning could possibly become a valuable alternative to classical machine learning for applications in High Energy Physics by offering computational speed-ups. In this study, we employ a support vector machine with a quantum kernel estimator (QSVM-Kernel method) to a recent LHC flagship physics analysis: $t\bar{t}H$ (Higgs boson production in association with a top quark pair). In… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.05059v2-abstract-full').style.display = 'inline'; document.getElementById('2104.05059v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.05059v2-abstract-full" style="display: none;"> Quantum machine learning could possibly become a valuable alternative to classical machine learning for applications in High Energy Physics by offering computational speed-ups. In this study, we employ a support vector machine with a quantum kernel estimator (QSVM-Kernel method) to a recent LHC flagship physics analysis: $t\bar{t}H$ (Higgs boson production in association with a top quark pair). In our quantum simulation study using up to 20 qubits and up to 50000 events, the QSVM-Kernel method performs as well as its classical counterparts in three different platforms from Google Tensorflow Quantum, IBM Quantum and Amazon Braket. Additionally, using 15 qubits and 100 events, the application of the QSVM-Kernel method on the IBM superconducting quantum hardware approaches the performance of a noiseless quantum simulator. Our study confirms that the QSVM-Kernel method can use the large dimensionality of the quantum Hilbert space to replace the classical feature space in realistic physics datasets. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.05059v2-abstract-full').style.display = 'none'; document.getElementById('2104.05059v2-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> 9 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Research 3, 033221 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.11560">arXiv:2012.11560</a> <span> [<a href="https://arxiv.org/pdf/2012.11560">pdf</a>, <a href="https://arxiv.org/format/2012.11560">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</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/10.1088/1361-6471/ac1391">10.1088/1361-6471/ac1391 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Application of Quantum Machine Learning using the Quantum Variational Classifier Method to High Energy Physics Analysis at the LHC on IBM Quantum Computer Simulator and Hardware with 10 qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wu%2C+S+L">Sau Lan Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Chan%2C+J">Jay Chan</a>, <a href="/search/quant-ph?searchtype=author&query=Guan%2C+W">Wen Guan</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+S">Shaojun Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Alex Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+C">Chen Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Livny%2C+M">Miron Livny</a>, <a href="/search/quant-ph?searchtype=author&query=Carminati%2C+F">Federico Carminati</a>, <a href="/search/quant-ph?searchtype=author&query=Di+Meglio%2C+A">Alberto Di Meglio</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+A+C+Y">Andy C. Y. Li</a>, <a href="/search/quant-ph?searchtype=author&query=Lykken%2C+J">Joseph Lykken</a>, <a href="/search/quant-ph?searchtype=author&query=Spentzouris%2C+P">Panagiotis Spentzouris</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+S+Y">Samuel Yen-Chi Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Yoo%2C+S">Shinjae Yoo</a>, <a href="/search/quant-ph?searchtype=author&query=Wei%2C+T">Tzu-Chieh Wei</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="2012.11560v2-abstract-short" style="display: inline;"> One of the major objectives of the experimental programs at the LHC is the discovery of new physics. This requires the identification of rare signals in immense backgrounds. Using machine learning algorithms greatly enhances our ability to achieve this objective. With the progress of quantum technologies, quantum machine learning could become a powerful tool for data analysis in high energy physic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.11560v2-abstract-full').style.display = 'inline'; document.getElementById('2012.11560v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.11560v2-abstract-full" style="display: none;"> One of the major objectives of the experimental programs at the LHC is the discovery of new physics. This requires the identification of rare signals in immense backgrounds. Using machine learning algorithms greatly enhances our ability to achieve this objective. With the progress of quantum technologies, quantum machine learning could become a powerful tool for data analysis in high energy physics. In this study, using IBM gate-model quantum computing systems, we employ the quantum variational classifier method in two recent LHC flagship physics analyses: $t\bar{t}H$ (Higgs boson production in association with a top quark pair) and $H\rightarrow渭^{+}渭^{-}$ (Higgs boson decays to two muons, probing the Higgs boson couplings to second-generation fermions). We have obtained early results with 10 qubits on the IBM quantum simulator and the IBM quantum hardware. With small training samples of 100 events on the quantum simulator, the quantum variational classifier method performs similarly to classical algorithms such as SVM (support vector machine) and BDT (boosted decision tree), which are often employed in LHC physics analyses. On the quantum hardware, the quantum variational classifier method has shown promising discrimination power, comparable to that on the quantum simulator. This study demonstrates that quantum machine learning has the ability to differentiate between signal and background in realistic physics datasets. We foresee the usage of quantum machine learning in future high-luminosity LHC physics analyses, including measurements of the Higgs boson self-couplings and searches for dark matter. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.11560v2-abstract-full').style.display = 'none'; document.getElementById('2012.11560v2-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> 21 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.01899">arXiv:2012.01899</a> <span> [<a href="https://arxiv.org/pdf/2012.01899">pdf</a>, <a href="https://arxiv.org/ps/2012.01899">ps</a>, <a href="https://arxiv.org/format/2012.01899">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1088/1674-1056/ac0bae">10.1088/1674-1056/ac0bae <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum Metrology with Coherent Superposition of Two Different Coded Channels </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="2012.01899v1-abstract-short" style="display: inline;"> We investigate the advantage of coherent superposition of two different coded channels in quantum metrology. In a continuous variable system, we show that the Heisenberg limit $1/N$ can be beaten by the coherent superposition without the help of indefinite causal order. And in parameter estimation, we demonstrate that the strategy with the coherent superposition can perform better than the strateg… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.01899v1-abstract-full').style.display = 'inline'; document.getElementById('2012.01899v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.01899v1-abstract-full" style="display: none;"> We investigate the advantage of coherent superposition of two different coded channels in quantum metrology. In a continuous variable system, we show that the Heisenberg limit $1/N$ can be beaten by the coherent superposition without the help of indefinite causal order. And in parameter estimation, we demonstrate that the strategy with the coherent superposition can perform better than the strategy with quantum \textsc{switch} which can generate indefinite causal order. We analytically obtain the general form of estimation precision in terms of the quantum Fisher information and further prove that the nonlinear Hamiltonian can improve the estimation precision and make the measurement uncertainty scale as $1/N^m$ for $m\geq2$. Our results can help to construct a high-precision measurement equipment, which can be applied to the detection of coupling strength and the test of time dilation and the modification of the canonical commutation relation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.01899v1-abstract-full').style.display = 'none'; document.getElementById('2012.01899v1-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, 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">6pages,2figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Chin. Phys. B, 2021, 30 (9): 090304 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.01890">arXiv:2012.01890</a> <span> [<a href="https://arxiv.org/pdf/2012.01890">pdf</a>, <a href="https://arxiv.org/ps/2012.01890">ps</a>, <a href="https://arxiv.org/format/2012.01890">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1016/j.rinp.2021.104430">10.1016/j.rinp.2021.104430 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Parameter estimation and quantum entanglement in PT symmetrical cavity magnonics system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+m">An min Wang</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="2012.01890v1-abstract-short" style="display: inline;"> We investigate the parameter estimation in a magnon-cavity-magnon coupled system. PT symmetrical two magnons system can be formed in the gain magnetic materials by the adiabatic elimination of the cavity field mode. We show that the optimal estimation will not appear at the exceptional point due to that the quantum fluctuations are the strongest at the exceptional point. Moreover, we demonstrate t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.01890v1-abstract-full').style.display = 'inline'; document.getElementById('2012.01890v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.01890v1-abstract-full" style="display: none;"> We investigate the parameter estimation in a magnon-cavity-magnon coupled system. PT symmetrical two magnons system can be formed in the gain magnetic materials by the adiabatic elimination of the cavity field mode. We show that the optimal estimation will not appear at the exceptional point due to that the quantum fluctuations are the strongest at the exceptional point. Moreover, we demonstrate that the measurements at the exceptional point tend to be optimal with the increase of prepared time. And the direct photon detection is the optimal measurement for the initial state in the vacuum input state. For the open PT symmetrical two magnons system, the quantum fluctuations will greatly reduce the degree of entanglement. Finally, we show that a higher estimated magnetic sensitivity can be obtained by measuring the frequency of one magnon in the PT symmetrical two magnons system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.01890v1-abstract-full').style.display = 'none'; document.getElementById('2012.01890v1-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, 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">6pages, 4figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Results in Physics 26 (2021) 104430 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2007.00246">arXiv:2007.00246</a> <span> [<a href="https://arxiv.org/pdf/2007.00246">pdf</a>, <a href="https://arxiv.org/ps/2007.00246">ps</a>, <a href="https://arxiv.org/format/2007.00246">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1007/s10773-021-04748-6">10.1007/s10773-021-04748-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optimizing Quantum Teleportation and Dense Coding via Mixed Noise Under Non-Markovian Approximation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Islam%2C+A">Akbar Islam</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Abliz%2C+A">Ahmad Abliz</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="2007.00246v1-abstract-short" style="display: inline;"> Physicists are attracted to open-system dynamics, how quantum systems evolve, and how they can protected from unnecessary environmental noise, especially environmental memory effects are not negligible, as with non-Markovian approximations. There are several methods to solve master equation of non-Markovian cases, we obtain the solutions of quantum-state-diffusion equation for a two qubit system u… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.00246v1-abstract-full').style.display = 'inline'; document.getElementById('2007.00246v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2007.00246v1-abstract-full" style="display: none;"> Physicists are attracted to open-system dynamics, how quantum systems evolve, and how they can protected from unnecessary environmental noise, especially environmental memory effects are not negligible, as with non-Markovian approximations. There are several methods to solve master equation of non-Markovian cases, we obtain the solutions of quantum-state-diffusion equation for a two qubit system using perturbation method, which under influence of various types of environmental noises, i.e., relaxation, dephasing and mix of them. We found that mixing these two types of noises benefit the quantum teleportation and quantum super-dense coding, that by introducing strong magnetic field on the relaxation processes will enhance quantum correlation in some time-scale. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.00246v1-abstract-full').style.display = 'none'; document.getElementById('2007.00246v1-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 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">7 pages, 6 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/1909.07441">arXiv:1909.07441</a> <span> [<a href="https://arxiv.org/pdf/1909.07441">pdf</a>, <a href="https://arxiv.org/format/1909.07441">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</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/10.1039/C9CP03951A">10.1039/C9CP03951A <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Attosecond Transient Absorption Spooktroscopy: a ghost imaging approach to ultrafast absorption spectroscopy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Driver%2C+T">Taran Driver</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+S">Siqi Li</a>, <a href="/search/quant-ph?searchtype=author&query=Champenois%2C+E+G">Elio G. Champenois</a>, <a href="/search/quant-ph?searchtype=author&query=Duris%2C+J">Joseph Duris</a>, <a href="/search/quant-ph?searchtype=author&query=Ratner%2C+D">Daniel Ratner</a>, <a href="/search/quant-ph?searchtype=author&query=Lane%2C+T">TJ Lane</a>, <a href="/search/quant-ph?searchtype=author&query=Rosenberger%2C+P">Philipp Rosenberger</a>, <a href="/search/quant-ph?searchtype=author&query=Al-Haddad%2C+A">Andre Al-Haddad</a>, <a href="/search/quant-ph?searchtype=author&query=Averbukh%2C+V">Vitali Averbukh</a>, <a href="/search/quant-ph?searchtype=author&query=Barnard%2C+T">Toby Barnard</a>, <a href="/search/quant-ph?searchtype=author&query=Berrah%2C+N">Nora Berrah</a>, <a href="/search/quant-ph?searchtype=author&query=Bostedt%2C+C">Christoph Bostedt</a>, <a href="/search/quant-ph?searchtype=author&query=Bucksbaum%2C+P+H">Philip H. Bucksbaum</a>, <a href="/search/quant-ph?searchtype=author&query=Coffee%2C+R">Ryan Coffee</a>, <a href="/search/quant-ph?searchtype=author&query=DiMauro%2C+L+F">Louis F. DiMauro</a>, <a href="/search/quant-ph?searchtype=author&query=Fang%2C+L">Li Fang</a>, <a href="/search/quant-ph?searchtype=author&query=Garratt%2C+D">Douglas Garratt</a>, <a href="/search/quant-ph?searchtype=author&query=Gatton%2C+A">Averell Gatton</a>, <a href="/search/quant-ph?searchtype=author&query=Guo%2C+Z">Zhaoheng Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Hartmann%2C+G">Gregor Hartmann</a>, <a href="/search/quant-ph?searchtype=author&query=Haxton%2C+D">Daniel Haxton</a>, <a href="/search/quant-ph?searchtype=author&query=Helml%2C+W">Wolfram Helml</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Z">Zhirong Huang</a>, <a href="/search/quant-ph?searchtype=author&query=LaForge%2C+A">Aaron LaForge</a>, <a href="/search/quant-ph?searchtype=author&query=Kamalov%2C+A">Andrei Kamalov</a> , et al. (16 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="1909.07441v1-abstract-short" style="display: inline;"> The recent demonstration of isolated attosecond pulses from an X-ray free-electron laser (XFEL) opens the possibility for probing ultrafast electron dynamics at X-ray wavelengths. An established experimental method for probing ultrafast dynamics is X-ray transient absorption spectroscopy, where the X-ray absorption spectrum is measured by scanning the central photon energy and recording the result… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.07441v1-abstract-full').style.display = 'inline'; document.getElementById('1909.07441v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1909.07441v1-abstract-full" style="display: none;"> The recent demonstration of isolated attosecond pulses from an X-ray free-electron laser (XFEL) opens the possibility for probing ultrafast electron dynamics at X-ray wavelengths. An established experimental method for probing ultrafast dynamics is X-ray transient absorption spectroscopy, where the X-ray absorption spectrum is measured by scanning the central photon energy and recording the resultant photoproducts. The spectral bandwidth inherent to attosecond pulses is wide compared to the resonant features typically probed, which generally precludes the application of this technique in the attosecond regime. In this paper we propose and demonstrate a new technique to conduct transient absorption spectroscopy with broad bandwidth attosecond pulses with the aid of ghost imaging, recovering sub-bandwidth resolution in photoproduct-based absorption measurements. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.07441v1-abstract-full').style.display = 'none'; document.getElementById('1909.07441v1-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> 16 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">13 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/1906.10728">arXiv:1906.10728</a> <span> [<a href="https://arxiv.org/pdf/1906.10728">pdf</a>, <a href="https://arxiv.org/format/1906.10728">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-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/10.1103/PhysRevA.102.023118">10.1103/PhysRevA.102.023118 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Electron Correlation Effects in Attosecond Photoionization of CO$_{2}$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Kamalov%2C+A">Andrei Kamalov</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+L">Anna L. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Bucksbaum%2C+P+H">Philip H. Bucksbaum</a>, <a href="/search/quant-ph?searchtype=author&query=Haxton%2C+D+J">Daniel J. Haxton</a>, <a href="/search/quant-ph?searchtype=author&query=Cryan%2C+J+P">James P. Cryan</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="1906.10728v1-abstract-short" style="display: inline;"> A technique for measuring photoionization time delays with attosecond precision is combined with calculations of photoionization matrix elements to demonstrate how multi-electron dynamics affect photoionization time delays in carbon dioxide. Electron correlation is observed to affect the time delays through two mechanisms: autoionization of molecular Rydberg states and accelerated escape from a co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.10728v1-abstract-full').style.display = 'inline'; document.getElementById('1906.10728v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1906.10728v1-abstract-full" style="display: none;"> A technique for measuring photoionization time delays with attosecond precision is combined with calculations of photoionization matrix elements to demonstrate how multi-electron dynamics affect photoionization time delays in carbon dioxide. Electron correlation is observed to affect the time delays through two mechanisms: autoionization of molecular Rydberg states and accelerated escape from a continuum shape resonance. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.10728v1-abstract-full').style.display = 'none'; document.getElementById('1906.10728v1-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 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 102, 023118 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1905.10782">arXiv:1905.10782</a> <span> [<a href="https://arxiv.org/pdf/1905.10782">pdf</a>, <a href="https://arxiv.org/format/1905.10782">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Study on Estimating Quantum Discord by Neural Network with Prior Knowledge </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yong-Lei Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">An-Min Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+G">Guo-Dong Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Sun%2C+Y">Yi Sun</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Peng-Fei Zhang</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="1905.10782v1-abstract-short" style="display: inline;"> Machine learning has achieved success in many areas because of its powerful fitting ability, so we hope it can help us to solve some significant physical quantitative problems, such as quantum correlation. In this research we will use neural networks to predict the value of quantum discord. Quantum discord is a measure of quantum correlation which is defined as the difference between quantum mutua… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.10782v1-abstract-full').style.display = 'inline'; document.getElementById('1905.10782v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.10782v1-abstract-full" style="display: none;"> Machine learning has achieved success in many areas because of its powerful fitting ability, so we hope it can help us to solve some significant physical quantitative problems, such as quantum correlation. In this research we will use neural networks to predict the value of quantum discord. Quantum discord is a measure of quantum correlation which is defined as the difference between quantum mutual information and classical correlation for a bipartite system. Since the definition contains an optimization term, it makes analytically solving hard. For some special cases and small systems, such as two-qubit systems and some X-states, the explicit solutions have been calculated. However, for general cases, we still know very little. Therefore, we study the feasibility of estimating quantum discord by machine learning method on two-qubit systems. In order to get an interpretable and high performance model, we modify the ordinary neural network by introducing some prior knowledge which come from the analysis about quantum discord. Our results show that prior knowledge actually improve the performance of neural network. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.10782v1-abstract-full').style.display = 'none'; document.getElementById('1905.10782v1-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 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2019. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1902.09675">arXiv:1902.09675</a> <span> [<a href="https://arxiv.org/pdf/1902.09675">pdf</a>, <a href="https://arxiv.org/format/1902.09675">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.3390/universe6070090">10.3390/universe6070090 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Langer Modification, Quantization condition and Barrier Penetration in Quantum Mechanics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+B">Bao-Fei Li</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+T">Tao Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Anzhong Wang</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="1902.09675v2-abstract-short" style="display: inline;"> The WKB approximation plays an essential role in the development of quantum mechanics and various important results have been obtained from it. In this paper, we introduce another method, {\it the so-called uniform asymptotic approximations}, which is an analytical approximation method to calculate the wave functions of the Schr枚dinger-like equations, and is applicable to various problems, includi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.09675v2-abstract-full').style.display = 'inline'; document.getElementById('1902.09675v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1902.09675v2-abstract-full" style="display: none;"> The WKB approximation plays an essential role in the development of quantum mechanics and various important results have been obtained from it. In this paper, we introduce another method, {\it the so-called uniform asymptotic approximations}, which is an analytical approximation method to calculate the wave functions of the Schr枚dinger-like equations, and is applicable to various problems, including cases with poles (singularities) and multiple turning points. An distinguished feature of the method is that in each order of the approximations the upper bounds of the errors are given explicitly. By properly choosing the freedom introduced in the method, the errors can be minimized, which significantly improves the accuracy of the calculations. A byproduct of the method is to provide a very clear explanation of the Langer modification encountered in the studies of the hydrogen atom and harmonic oscillator. To further test our method, we calculate (analytically) the wave functions for several exactly solvable potentials of the Schr枚dinger equation, and then obtain the transmission coefficients of particles over potential barriers, as well as the quantization conditions for bound states. We find that such obtained results agree with the exact ones extremely well. Possible applications of the method to other fields are also discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.09675v2-abstract-full').style.display = 'none'; document.getElementById('1902.09675v2-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 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 February, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">revtex4-1, 1 figures, and 1 table. Published in Universe 6 (2020) 90</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Universe 6, 90 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1708.04540">arXiv:1708.04540</a> <span> [<a href="https://arxiv.org/pdf/1708.04540">pdf</a>, <a href="https://arxiv.org/ps/1708.04540">ps</a>, <a href="https://arxiv.org/format/1708.04540">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Systems and Control">eess.SY</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/10.1088/1674-1056/27/6/060303">10.1088/1674-1056/27/6/060303 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum estimation of detection efficiency with no-knowledge quantum feedback </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jianyong Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Anmin Wang</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="1708.04540v1-abstract-short" style="display: inline;"> We investigate that no-knowledge measurement-based feedback control is utilized to obtain the estimation precision of the detection efficiency. For the feedback operators that concern us, no-knowledge measurement is the optimal way to estimate the detection efficiency. We show that the higher precision can be achieved for the lower or larger detection efficiency. It is found that no-knowledge feed… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.04540v1-abstract-full').style.display = 'inline'; document.getElementById('1708.04540v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1708.04540v1-abstract-full" style="display: none;"> We investigate that no-knowledge measurement-based feedback control is utilized to obtain the estimation precision of the detection efficiency. For the feedback operators that concern us, no-knowledge measurement is the optimal way to estimate the detection efficiency. We show that the higher precision can be achieved for the lower or larger detection efficiency. It is found that no-knowledge feedback can be used to cancel decoherence. No-knowledge feedback with a high detection efficiency can perform well in estimating frequency and detection efficiency parameters simultaneously. And simultaneous estimation is better than independent estimation given by the same probes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.04540v1-abstract-full').style.display = 'none'; document.getElementById('1708.04540v1-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 August, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">7pages, 3figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Chin. Phys. B Vol. 27, No. 6 (2018) 060303 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1708.01357">arXiv:1708.01357</a> <span> [<a href="https://arxiv.org/pdf/1708.01357">pdf</a>, <a href="https://arxiv.org/ps/1708.01357">ps</a>, <a href="https://arxiv.org/format/1708.01357">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1007/s11128-018-1884-z">10.1007/s11128-018-1884-z <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> High-dimensional cryptographic quantum parameter estimation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jianyong Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="1708.01357v2-abstract-short" style="display: inline;"> We investigate cryptographic quantum parameter estimation with a high-dimensional system that allows only Bob (Receiver) to access the result and achieve optimal parameter precision from Alice (Sender). Eavesdropper (Eve) only can disturb the parameter estimation of Bob, but she can not obtain the information of parameter. We analyze the security and show that the high-dimensional system can help… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.01357v2-abstract-full').style.display = 'inline'; document.getElementById('1708.01357v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1708.01357v2-abstract-full" style="display: none;"> We investigate cryptographic quantum parameter estimation with a high-dimensional system that allows only Bob (Receiver) to access the result and achieve optimal parameter precision from Alice (Sender). Eavesdropper (Eve) only can disturb the parameter estimation of Bob, but she can not obtain the information of parameter. We analyze the security and show that the high-dimensional system can help to utilize the resource to obtain better precision than the two-dimensional system. Finally, we generalize it to the case of multi-parameter. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.01357v2-abstract-full').style.display = 'none'; document.getElementById('1708.01357v2-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, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 August, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">6pages</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Quantum Inf Process (2018) 17:116 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1608.07684">arXiv:1608.07684</a> <span> [<a href="https://arxiv.org/pdf/1608.07684">pdf</a>, <a href="https://arxiv.org/ps/1608.07684">ps</a>, <a href="https://arxiv.org/format/1608.07684">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/PhysRevA.95.012117">10.1103/PhysRevA.95.012117 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum metrology in coarsened measurement reference </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Anmin Wang</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="1608.07684v2-abstract-short" style="display: inline;"> We investigate the role of coarsened measurement reference in quantum metrology. Coarsened measurement reference comes from the coarsened reference time and basis. When the measurement based on one common reference basis, the disadvantage can be removed by symmetry. Due to the coarsened reference basis, entangled states can not perform better than product states for large number of probe particles… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.07684v2-abstract-full').style.display = 'inline'; document.getElementById('1608.07684v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1608.07684v2-abstract-full" style="display: none;"> We investigate the role of coarsened measurement reference in quantum metrology. Coarsened measurement reference comes from the coarsened reference time and basis. When the measurement based on one common reference basis, the disadvantage can be removed by symmetry. Due to the coarsened reference basis, entangled states can not perform better than product states for large number of probe particles. Given a finite uncertainty of the coarsened reference basis, the optimal number of probe particle is obtained in estimating phase. Finally, we prove that the maximally entangled state always achieves better precision under the case of non-Markovian dephasing than that under the case of Markovian dephasing. The product state is more resistant to interference of the coarsened reference time than the entangled state. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.07684v2-abstract-full').style.display = 'none'; document.getElementById('1608.07684v2-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> 17 January, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 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">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 1figure</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 95, 012117 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1608.06370">arXiv:1608.06370</a> <span> [<a href="https://arxiv.org/pdf/1608.06370">pdf</a>, <a href="https://arxiv.org/ps/1608.06370">ps</a>, <a href="https://arxiv.org/format/1608.06370">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1016/j.physleta.2017.07.036">10.1016/j.physleta.2017.07.036 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Michelson interferometer for measuring temperature </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=wang%2C+A">Anmin wang</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="1608.06370v1-abstract-short" style="display: inline;"> We investigate that temperature can be measured by a modified Michelson interferometer, where at least one reflected mirror is replaced by a thermalized sample. Both of two mirrors replaced by the corresponding two thermalized samples can help to approximatively improve the resolution of temperature up to twice than only one mirror replaced by a thermalized sample. For further improving the precis… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.06370v1-abstract-full').style.display = 'inline'; document.getElementById('1608.06370v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1608.06370v1-abstract-full" style="display: none;"> We investigate that temperature can be measured by a modified Michelson interferometer, where at least one reflected mirror is replaced by a thermalized sample. Both of two mirrors replaced by the corresponding two thermalized samples can help to approximatively improve the resolution of temperature up to twice than only one mirror replaced by a thermalized sample. For further improving the precision, a nonlinear medium can be employed. The Michelson interferometer is embedded in a gas displaying Kerr nonlinearity. We obtain the analytical equations and numerically calculate the precision with parameters within the reach of current technology, proving that the precision of temperature can be greatly enhanced by using a nonlinear medium. Our results show that one can create an accurate thermometer by measuring the photons in the Michelson interferometer, with no need for directly measuring the population of thermalized sample. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.06370v1-abstract-full').style.display = 'none'; document.getElementById('1608.06370v1-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> 22 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">Comments:</span> <span class="has-text-grey-dark mathjax">8pages, 1figure</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Physics Letters A 381 (2017) 3038 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1604.04955">arXiv:1604.04955</a> <span> [<a href="https://arxiv.org/pdf/1604.04955">pdf</a>, <a href="https://arxiv.org/ps/1604.04955">ps</a>, <a href="https://arxiv.org/format/1604.04955">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1007/s11128-017-1605-z">10.1007/s11128-017-1605-z <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optimal Quantum Thermometry by Dephasing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Anmin Wang</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="1604.04955v1-abstract-short" style="display: inline;"> Decoherence often happens in the quantum world. We try to utilize quantum dephasing to build an optimal thermometry. By calculating the Cram$\acute{e}$r-Rao bound, we prove that the Ramsey measurement is the optimal way to measure the temperature for uncorrelated particles. Using the optimal measurement, the metrological equivalence of product and maximally entangled states of initial quantum prob… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.04955v1-abstract-full').style.display = 'inline'; document.getElementById('1604.04955v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1604.04955v1-abstract-full" style="display: none;"> Decoherence often happens in the quantum world. We try to utilize quantum dephasing to build an optimal thermometry. By calculating the Cram$\acute{e}$r-Rao bound, we prove that the Ramsey measurement is the optimal way to measure the temperature for uncorrelated particles. Using the optimal measurement, the metrological equivalence of product and maximally entangled states of initial quantum probes that always holds. However, using Ramsey measurement, the metrological equivalence only holds in special situation. Contrary to frequency estimation, the quantum limit can be surpassed under the case $谓<1$. For the general Zeno regime($谓=2$), uncorrelated product states are the optimal choose in typical Ramsey spectroscopy set-up. In order to surpass the standard scaling, we propose to change the interaction strength with time. Finally, we investigate other environmental influences on the measurement precision of temperature. Base on it, we define a new way to measure non-Markovian effect. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.04955v1-abstract-full').style.display = 'none'; document.getElementById('1604.04955v1-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> 17 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">Comments:</span> <span class="has-text-grey-dark mathjax">8pages</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Quantum Inf Process (2017) 16: 155 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1511.00001">arXiv:1511.00001</a> <span> [<a href="https://arxiv.org/pdf/1511.00001">pdf</a>, <a href="https://arxiv.org/ps/1511.00001">ps</a>, <a href="https://arxiv.org/format/1511.00001">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1142/S0217984917502141">10.1142/S0217984917502141 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gravitational time dilation induced decoherence during spontaneous emission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Xu%2C+C">Chunling Xu</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Anmin Wang</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="1511.00001v1-abstract-short" style="display: inline;"> We investigate decoherence of quantum superpositions induced by gravitational time dilation and spontaneous emission between two atomic levels. It has been shown that gravitational time dilation can be an universal decoherence source. Here, we consider decoherence induced by gravitational time dilation only in the situation of spontaneous emission. Then, we obtain that the coherence of particle's… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.00001v1-abstract-full').style.display = 'inline'; document.getElementById('1511.00001v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1511.00001v1-abstract-full" style="display: none;"> We investigate decoherence of quantum superpositions induced by gravitational time dilation and spontaneous emission between two atomic levels. It has been shown that gravitational time dilation can be an universal decoherence source. Here, we consider decoherence induced by gravitational time dilation only in the situation of spontaneous emission. Then, we obtain that the coherence of particle's position state depends on reference frame due to the time dilation changing the distinguishability of emission photon from two positions of particle. Changing the direction of light field can also result in the difference about the coherence of quantum superpositions. For observing the decoherence effect mainly due to gravitational time dilation, time-delayed feedback can be utilized to increase the decoherence of particle's superpositions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.00001v1-abstract-full').style.display = 'none'; document.getElementById('1511.00001v1-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 October, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">7pages,4figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Modern Physics Letters B Vol. 31, No. 23 (2017) 1750214 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1410.2779">arXiv:1410.2779</a> <span> [<a href="https://arxiv.org/pdf/1410.2779">pdf</a>, <a href="https://arxiv.org/ps/1410.2779">ps</a>, <a href="https://arxiv.org/format/1410.2779">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantization of the Location Stage of Hotelling Model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yuannan Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Qin%2C+G">Gan Qin</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="1410.2779v1-abstract-short" style="display: inline;"> We present the classical Hotelling model we want to quantize, and investigate the quantum consequences of the game. Our results demonstrate that the quantum game give higher profit for both players, and that with the quantum entanglement parameter increasing, the quantum benefit over the classical increases too. Then we extend the model to a more general form, and quantum advantage keeps unchanged… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.2779v1-abstract-full').style.display = 'inline'; document.getElementById('1410.2779v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1410.2779v1-abstract-full" style="display: none;"> We present the classical Hotelling model we want to quantize, and investigate the quantum consequences of the game. Our results demonstrate that the quantum game give higher profit for both players, and that with the quantum entanglement parameter increasing, the quantum benefit over the classical increases too. Then we extend the model to a more general form, and quantum advantage keeps unchanged. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.2779v1-abstract-full').style.display = 'none'; document.getElementById('1410.2779v1-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, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2014. </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">11 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/1409.0191">arXiv:1409.0191</a> <span> [<a href="https://arxiv.org/pdf/1409.0191">pdf</a>, <a href="https://arxiv.org/ps/1409.0191">ps</a>, <a href="https://arxiv.org/format/1409.0191">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Information Theory">cs.IT</span> </div> </div> <p class="title is-5 mathjax"> Continuous quantum measurement in spin environments </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="1409.0191v1-abstract-short" style="display: inline;"> We derive a formalism of stochastic master equations (SME) which describes the decoherence dynamics of a system in spin environments conditioned on the measurement record. Markovian and non-Markovian nature of environment can be revealed by a spectroscopy method based on weak quantum measurement (weak spectroscopy). On account of that correlated environments can lead to a nonlocal open system whic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.0191v1-abstract-full').style.display = 'inline'; document.getElementById('1409.0191v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1409.0191v1-abstract-full" style="display: none;"> We derive a formalism of stochastic master equations (SME) which describes the decoherence dynamics of a system in spin environments conditioned on the measurement record. Markovian and non-Markovian nature of environment can be revealed by a spectroscopy method based on weak quantum measurement (weak spectroscopy). On account of that correlated environments can lead to a nonlocal open system which exhibits strong non-Markovian effects although the local dynamics are Markovian, the spectroscopy method can be used to demonstrate that there is correlation between two environments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.0191v1-abstract-full').style.display = 'none'; document.getElementById('1409.0191v1-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> 31 August, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2014. </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,5 figures. arXiv admin note: text overlap with arXiv:1307.2101 by other authors</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1404.5179">arXiv:1404.5179</a> <span> [<a href="https://arxiv.org/pdf/1404.5179">pdf</a>, <a href="https://arxiv.org/ps/1404.5179">ps</a>, <a href="https://arxiv.org/format/1404.5179">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1088/1674-1056/25/11/110302">10.1088/1674-1056/25/11/110302 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Degree of Fuzziness in Coarsened Measurement References </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="1404.5179v1-abstract-short" style="display: inline;"> It has been found that the quantum-to-classical transition can be observed independent of macroscopicity of the quantum state for a fixed degree of fuzziness in the coarsened references of measurements. Here, a general situation, that is the degree of fuzziness can change with the rotation angle between two states (different rotation angles represent different references), is researched based on t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1404.5179v1-abstract-full').style.display = 'inline'; document.getElementById('1404.5179v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1404.5179v1-abstract-full" style="display: none;"> It has been found that the quantum-to-classical transition can be observed independent of macroscopicity of the quantum state for a fixed degree of fuzziness in the coarsened references of measurements. Here, a general situation, that is the degree of fuzziness can change with the rotation angle between two states (different rotation angles represent different references), is researched based on the reason that the fuzziness of reference can come from two kinds: the Hamiltonian (rotation frequency) and the timing (rotation time). Our results show that, for the fuzziness of Hamiltonian alone, the degree of fuzziness for reference will change with the rotation angle between two states and the quantum effects can still be observed no matter how much degree of fuzziness of Hamiltonian; for the fuzziness of timing, the degree of coarsening reference is unchanged with the rotation angle. Moreover, during the rotation of the measurement axis, the decoherence environment can also help the classical-to-quantum transition due to changing the direction of measurement axis. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1404.5179v1-abstract-full').style.display = 'none'; document.getElementById('1404.5179v1-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> 21 April, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2014. </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,5figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Chin. Phys. B Vol. 25, No. 11 (2016) 110302 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1312.7178">arXiv:1312.7178</a> <span> [<a href="https://arxiv.org/pdf/1312.7178">pdf</a>, <a href="https://arxiv.org/ps/1312.7178">ps</a>, <a href="https://arxiv.org/format/1312.7178">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1142/S0219749915500185">10.1142/S0219749915500185 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Generation of multi-photon entanglement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="1312.7178v1-abstract-short" style="display: inline;"> We propose a new scheme to generate the multi-photon entanglement via two steps, that is, first to utilize the superconductor to create the multi-quantum-dot entanglement, and then to use the input photon to transfer it into the multi-photon entanglement. Moreover, the maximum probability for the swap of photon and quantum-dot qubits is close to unit for a single input Gaussian photon. More import… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1312.7178v1-abstract-full').style.display = 'inline'; document.getElementById('1312.7178v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1312.7178v1-abstract-full" style="display: none;"> We propose a new scheme to generate the multi-photon entanglement via two steps, that is, first to utilize the superconductor to create the multi-quantum-dot entanglement, and then to use the input photon to transfer it into the multi-photon entanglement. Moreover, the maximum probability for the swap of photon and quantum-dot qubits is close to unit for a single input Gaussian photon. More importantly, by mapping the multi-quantum-dot state into the coherent states of oscillators, such as cavity modes, the multi-quantum-dot entanglement in our scheme can be protected from the decoherence induced by the noise. Thus, it is possible to generate more than eight spatially separated entangled photons in the realistic experimental conditions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1312.7178v1-abstract-full').style.display = 'none'; document.getElementById('1312.7178v1-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 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">5pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> International Journal of Quantum Information Vol. 13 (2015) 1550018 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1310.3089">arXiv:1310.3089</a> <span> [<a href="https://arxiv.org/pdf/1310.3089">pdf</a>, <a href="https://arxiv.org/ps/1310.3089">ps</a>, <a href="https://arxiv.org/format/1310.3089">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Entanglement entropy in quasi-symmetric multi-qubit states </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhi-Hua Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">An-Min Wang</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="1310.3089v1-abstract-short" style="display: inline;"> We generalize the symmetric multi-qubit states to their q-analogs, whose basis vectors are identified with the q-Dicke states. We study the entanglement entropy in these states and find that entanglement is extruded towards certain regions of the system due to the inhomogeneity aroused by q-deformation. We also calculate entanglement entropy in ground states of a related q-deformed Lipkin-Meshkov-… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1310.3089v1-abstract-full').style.display = 'inline'; document.getElementById('1310.3089v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1310.3089v1-abstract-full" style="display: none;"> We generalize the symmetric multi-qubit states to their q-analogs, whose basis vectors are identified with the q-Dicke states. We study the entanglement entropy in these states and find that entanglement is extruded towards certain regions of the system due to the inhomogeneity aroused by q-deformation. We also calculate entanglement entropy in ground states of a related q-deformed Lipkin-Meshkov-Glick model and show that the singularities of entanglement can correctly signify the quantum phase transition points for different strengths of q-deformation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1310.3089v1-abstract-full').style.display = 'none'; document.getElementById('1310.3089v1-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 October, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">11 pages, 2 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/1309.0312">arXiv:1309.0312</a> <span> [<a href="https://arxiv.org/pdf/1309.0312">pdf</a>, <a href="https://arxiv.org/ps/1309.0312">ps</a>, <a href="https://arxiv.org/format/1309.0312">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1140/epjd/e2013-40395-7">10.1140/epjd/e2013-40395-7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Secure communication with choice of measurement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="1309.0312v2-abstract-short" style="display: inline;"> It has been found that the signal can be encoded in the choice of the measurement basis of one of the communicating parties, while the outcomes of the measurement are irrelevant for the communication and therefore may be discarded. The proposed protocol was novel and interesting, but it wasn't secure for communication. The eavesdropper can obtain the information without being detected. We utilize… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1309.0312v2-abstract-full').style.display = 'inline'; document.getElementById('1309.0312v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1309.0312v2-abstract-full" style="display: none;"> It has been found that the signal can be encoded in the choice of the measurement basis of one of the communicating parties, while the outcomes of the measurement are irrelevant for the communication and therefore may be discarded. The proposed protocol was novel and interesting, but it wasn't secure for communication. The eavesdropper can obtain the information without being detected. We utilize the outcomes of the measurement to propose a secure communication protocol. And the error correction code is used to increase the fault tolerance in the noise. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1309.0312v2-abstract-full').style.display = 'none'; document.getElementById('1309.0312v2-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 February, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 September, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">2figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> European Physical Journal D (2014) Volume 68, Issue 10 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1306.5065">arXiv:1306.5065</a> <span> [<a href="https://arxiv.org/pdf/1306.5065">pdf</a>, <a href="https://arxiv.org/ps/1306.5065">ps</a>, <a href="https://arxiv.org/format/1306.5065">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1016/j.physleta.2014.06.006">10.1016/j.physleta.2014.06.006 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum Metrology in Correlated Environments </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="1306.5065v2-abstract-short" style="display: inline;"> We analytically obtain the precision bounds of frequency measurements in correlated Markovian and non-Markovian environments by using a variational approach. It is verified that in standard Ramsey spectroscopy setup, the metrological equivalence of product and maximally entangled states persists in maximally correlated Markovian and non-Markovian environments. We find that the optimal measurement… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1306.5065v2-abstract-full').style.display = 'inline'; document.getElementById('1306.5065v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1306.5065v2-abstract-full" style="display: none;"> We analytically obtain the precision bounds of frequency measurements in correlated Markovian and non-Markovian environments by using a variational approach. It is verified that in standard Ramsey spectroscopy setup, the metrological equivalence of product and maximally entangled states persists in maximally correlated Markovian and non-Markovian environments. We find that the optimal measurement can achieve a much higher resolution than standard Ramsey spectroscopy in the correlated environments. When the number of particles in the maximally entangled states is even, the precision bound decreases with interrogation time; and when the number is odd, the precision bound is independent of interrogation time, both in correlated Markovian and general non-Markovian environments. In addition, the opposite case can appear in some special non-Markovian environments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1306.5065v2-abstract-full').style.display = 'none'; document.getElementById('1306.5065v2-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 December, 2013; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 June, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Physics Letters A Vol. 378 (2014) 2079 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1301.5866">arXiv:1301.5866</a> <span> [<a href="https://arxiv.org/pdf/1301.5866">pdf</a>, <a href="https://arxiv.org/ps/1301.5866">ps</a>, <a href="https://arxiv.org/format/1301.5866">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Remote implementation of partially unknown operations and its entanglement costs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Luo%2C+S">Shu-Hui Luo</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">An-Min Wang</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="1301.5866v1-abstract-short" style="display: inline;"> We present the generalized version of Wang's protocol[A.M.Wang, Phys.Rev.A 74,032317 (2006)] for the remote implementation(sometimes referred to as quantum remote control) of partially unknown quantum operations. The protocol only requires no more than half of the entanglements used in Bidirectional Quantum State Teleportation. We also propose a protocol for another form of quantum remote control.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1301.5866v1-abstract-full').style.display = 'inline'; document.getElementById('1301.5866v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1301.5866v1-abstract-full" style="display: none;"> We present the generalized version of Wang's protocol[A.M.Wang, Phys.Rev.A 74,032317 (2006)] for the remote implementation(sometimes referred to as quantum remote control) of partially unknown quantum operations. The protocol only requires no more than half of the entanglements used in Bidirectional Quantum State Teleportation. We also propose a protocol for another form of quantum remote control. It can remotely implement a unitary operation which is a combination of the projective representations of a group. Moreover, we prove that the Schmidt rank of the entanglements cannot not be less than the number of controlled parameters of the operations, which for the first time gives a lower bound on entanglement costs in remote implementation of quantum operations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1301.5866v1-abstract-full').style.display = 'none'; document.getElementById('1301.5866v1-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 January, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">9 pages, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1212.5680">arXiv:1212.5680</a> <span> [<a href="https://arxiv.org/pdf/1212.5680">pdf</a>, <a href="https://arxiv.org/ps/1212.5680">ps</a>, <a href="https://arxiv.org/format/1212.5680">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1088/1674-1056/23/4/040302">10.1088/1674-1056/23/4/040302 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Nonlocal Non-Markovian Effects in Dephasing Environments </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Xie%2C+D">Dong Xie</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="1212.5680v4-abstract-short" style="display: inline;"> We study the nonlocal non-Markovian effects through local interactions between two subsystems and the corresponding two environments. It has been found that the initial correlations between two environments can turn a Markovian to a non-Markovian regime with the extra control on the local interaction time. We further research the nonlocal non-Markovian effects from two situations: without extra co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1212.5680v4-abstract-full').style.display = 'inline'; document.getElementById('1212.5680v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1212.5680v4-abstract-full" style="display: none;"> We study the nonlocal non-Markovian effects through local interactions between two subsystems and the corresponding two environments. It has been found that the initial correlations between two environments can turn a Markovian to a non-Markovian regime with the extra control on the local interaction time. We further research the nonlocal non-Markovian effects from two situations: without extra control, the nonlocal non-Markovian effects only appear under the condition that two local dynamics are non-Markovian-non-Markovian(both of two local dynamics are non-Markovian), or Markovian-non-Markovian, never appear under the condition of Markovian-Markovian; with extra control, the nonlocal non-Markovian effects can occur under the condition of Markovian-Markovian. It shows that the correlations between two environments has an upper bound: only making a flow of information from the environment back to the global system begin finitely earlier than that back to any one of two local systems, not infinitely. Then, due to observing that the classical correlations between two environments have the same function as the quantum correlations, we advise two special ways to distribute classical correlations between two environments without initial correlations. Finally, from numerical solutions in the spin star configuration we obtain that the self-correlation(internal correlation) of each environment promotes the nonlocal non-Markovian effects. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1212.5680v4-abstract-full').style.display = 'none'; document.getElementById('1212.5680v4-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 June, 2013; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 December, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Chin. Phys. B Vol. 23, No. 4 (2014) 040302 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1203.6483">arXiv:1203.6483</a> <span> [<a href="https://arxiv.org/pdf/1203.6483">pdf</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="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/10.1088/1742-6596/324/1/012032">10.1088/1742-6596/324/1/012032 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gaussian fluctuations in an ideal bose-gas -- a simple model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Petrova%2C+A">A Petrova</a>, <a href="/search/quant-ph?searchtype=author&query=Nedopekin%2C+O">O Nedopekin</a>, <a href="/search/quant-ph?searchtype=author&query=Tayurskii%2C+D">D Tayurskii</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Q+A">Q A Wang</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="1203.6483v1-abstract-short" style="display: inline;"> Based on the canonical ensemble, we suggested the simple scheme for taking into account Gaussian fluctuations in a finite system of ideal boson gas. Within framework of scheme we investigated the influence of fluctuations on the particle distribution in Bose -gas for two cases - with taking into account the number of particles in the ground state and without this assumption. The temperature and fl… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1203.6483v1-abstract-full').style.display = 'inline'; document.getElementById('1203.6483v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1203.6483v1-abstract-full" style="display: none;"> Based on the canonical ensemble, we suggested the simple scheme for taking into account Gaussian fluctuations in a finite system of ideal boson gas. Within framework of scheme we investigated the influence of fluctuations on the particle distribution in Bose -gas for two cases - with taking into account the number of particles in the ground state and without this assumption. The temperature and fluctuation parameter dependences of the modified Bose- Einstein distribution have been determined. Also the dependence of the condensation temperature on the fluctuation distribution parameter has been obtained. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1203.6483v1-abstract-full').style.display = 'none'; document.getElementById('1203.6483v1-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 March, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2012. </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">arXiv admin note: text overlap with arXiv:cond-mat/0408599</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Journal of Physics: Conference Series 324 (2011) 012032 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1108.1607">arXiv:1108.1607</a> <span> [<a href="https://arxiv.org/pdf/1108.1607">pdf</a>, <a href="https://arxiv.org/ps/1108.1607">ps</a>, <a href="https://arxiv.org/format/1108.1607">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</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="Nuclear Theory">nucl-th</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/10.1088/0253-6102/58/5/04">10.1088/0253-6102/58/5/04 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Exact Eigenfunctions of $N$-Body system with Quadratic Pair Potential </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zhaoliang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A">Anmin Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+Y">Yang Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+X">Xuechao Li</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="1108.1607v4-abstract-short" style="display: inline;"> We obtain all the exact eigenvalues and the corresponding eigenfunctions of $N$-body Bose and Fermi systems with Quadratic Pair Potentials in one dimension. The originally existed first excited state level is missing in one dimension, which results from the operation of symmetry or antisymmetry of identical particles. In two and higher dimensions, we give all the eigenvalues and the analytical gro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1108.1607v4-abstract-full').style.display = 'inline'; document.getElementById('1108.1607v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1108.1607v4-abstract-full" style="display: none;"> We obtain all the exact eigenvalues and the corresponding eigenfunctions of $N$-body Bose and Fermi systems with Quadratic Pair Potentials in one dimension. The originally existed first excited state level is missing in one dimension, which results from the operation of symmetry or antisymmetry of identical particles. In two and higher dimensions, we give all the eigenvalues and the analytical ground state wave functions and the number of degeneracy. Through the comparison with Avinash Khare's results, we have perfected his results. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1108.1607v4-abstract-full').style.display = 'none'; document.getElementById('1108.1607v4-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> 23 February, 2012; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 August, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2011. </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,1 figure</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1001.0116">arXiv:1001.0116</a> <span> [<a href="https://arxiv.org/pdf/1001.0116">pdf</a>, <a href="https://arxiv.org/ps/1001.0116">ps</a>, <a href="https://arxiv.org/format/1001.0116">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1088/1751-8113/43/16/165204">10.1088/1751-8113/43/16/165204 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> One Dimensional Magnetized TG Gas Properties in an External Magnetic Field </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z+L">Zhao Liang Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="1001.0116v1-abstract-short" style="display: inline;"> With Girardeau's Fermi-Bose mapping, we have constructed the eigenstates of a TG gas in an external magnetic field. When the number of bosons $N$ is commensurate with the number of potential cycles $M$, the probability of this TG gas in the ground state is bigger than the TG gas raised by Girardeau in 1960. Through the comparison of properties between this TG gas and Fermi gas, we find that the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1001.0116v1-abstract-full').style.display = 'inline'; document.getElementById('1001.0116v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1001.0116v1-abstract-full" style="display: none;"> With Girardeau's Fermi-Bose mapping, we have constructed the eigenstates of a TG gas in an external magnetic field. When the number of bosons $N$ is commensurate with the number of potential cycles $M$, the probability of this TG gas in the ground state is bigger than the TG gas raised by Girardeau in 1960. Through the comparison of properties between this TG gas and Fermi gas, we find that the following issues are always of the same: their average value of particle's coordinate and potential energy, system's total momentum, single-particle density and the pair distribution function. But the reduced single-particle matrices and their momentum distributions between them are different. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1001.0116v1-abstract-full').style.display = 'none'; document.getElementById('1001.0116v1-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> 31 December, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2010. </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> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0911.2144">arXiv:0911.2144</a> <span> [<a href="https://arxiv.org/pdf/0911.2144">pdf</a>, <a href="https://arxiv.org/ps/0911.2144">ps</a>, <a href="https://arxiv.org/format/0911.2144">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum Mechanics in the general quantum systems (VI): exact series solution of stationary Schr枚dinger's equation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="0911.2144v4-abstract-short" style="display: inline;"> We obtain a complete series solution of stationary Schr枚dinger's equation in the general quantum systems. It is exact in the sense that any approximation means is not used, or that the whole corrections or contributions from all order perturbations are involved if the perturbation concept is introduced. Furthermore, the useful forms of our exact solution and a new expression the complete Green o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0911.2144v4-abstract-full').style.display = 'inline'; document.getElementById('0911.2144v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0911.2144v4-abstract-full" style="display: none;"> We obtain a complete series solution of stationary Schr枚dinger's equation in the general quantum systems. It is exact in the sense that any approximation means is not used, or that the whole corrections or contributions from all order perturbations are involved if the perturbation concept is introduced. Furthermore, the useful forms of our exact solution and a new expression the complete Green operator are given out. As a universal and analytical solution, it is helpful for the theoretical derivations and practical calculations in quantum theory. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0911.2144v4-abstract-full').style.display = 'none'; document.getElementById('0911.2144v4-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> 22 December, 2009; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 November, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2009. </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">Add the new rsults to the third version. 7 pages. No figure. This is the sixth manuscript. Previous manuscripts see arXiv:quant-ph/0611216, arXiv:quant-ph/0611217, arXiv:quant-ph/0601051, arXiv:quant-ph/0612068 and arXiv:0911.0347</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0911.0347">arXiv:0911.0347</a> <span> [<a href="https://arxiv.org/pdf/0911.0347">pdf</a>, <a href="https://arxiv.org/ps/0911.0347">ps</a>, <a href="https://arxiv.org/format/0911.0347">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum mechanics in the general quantum systems (V): Hamiltonian eigenvalues </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Li%2C+Z">Zhou Li</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="0911.0347v1-abstract-short" style="display: inline;"> We derive out a complete series expression of Hamiltonian eigenvalues without any approximation and cut in the general quantum systems based on Wang's formal framework \cite{wang1}. In particular, we then propose a calculating approach of eigenvalues of arbitrary Hamiltonian via solving an algebra equation satisfied by a kernal function, which involves the contributions from all order perturbati… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0911.0347v1-abstract-full').style.display = 'inline'; document.getElementById('0911.0347v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0911.0347v1-abstract-full" style="display: none;"> We derive out a complete series expression of Hamiltonian eigenvalues without any approximation and cut in the general quantum systems based on Wang's formal framework \cite{wang1}. In particular, we then propose a calculating approach of eigenvalues of arbitrary Hamiltonian via solving an algebra equation satisfied by a kernal function, which involves the contributions from all order perturbations. In order to verify the validity of our expressions and reveal the power of our approach, we calculate the ground state energy of a quartic anharmonic oscillator and have obtained good enough results comparing with the known one. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0911.0347v1-abstract-full').style.display = 'none'; document.getElementById('0911.0347v1-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 November, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2009. </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">18 pages, No figure. This is the fifth manuscript. Previous manuscripts see arXiv:quant-ph/0611216, arXiv:quant-ph/0611217, arXiv:quant-ph/0601051 and arXiv:quant-ph/0612068</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0902.2432">arXiv:0902.2432</a> <span> [<a href="https://arxiv.org/pdf/0902.2432">pdf</a>, <a href="https://arxiv.org/ps/0902.2432">ps</a>, <a href="https://arxiv.org/format/0902.2432">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1140/epjd/e2009-00232-4">10.1140/epjd/e2009-00232-4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum-state transfer on spin-chain channels with random imperfection </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Kong%2C+D">De-Xin Kong</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="0902.2432v3-abstract-short" style="display: inline;"> We investigate the quantum-state transfer on spin-chian channels with random imperfections.Through combining the advantages of two known schemes, the dual-rail spin-chain channels[9] and the particular ihhomogenous spin-chain channel[10], we propose a protocol that can avoid the quantum noises introduced by many unnecessary measurements and can enhance the anti-decoherence ability. The results s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0902.2432v3-abstract-full').style.display = 'inline'; document.getElementById('0902.2432v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0902.2432v3-abstract-full" style="display: none;"> We investigate the quantum-state transfer on spin-chian channels with random imperfections.Through combining the advantages of two known schemes, the dual-rail spin-chain channels[9] and the particular ihhomogenous spin-chain channel[10], we propose a protocol that can avoid the quantum noises introduced by many unnecessary measurements and can enhance the anti-decoherence ability. The results show that our protocol is more efficient to transfer an arbitrary quantum state than the original one. In particular, we discuss the effects of couplings fluctuations and imperfect initialization on both of the improved scheme and original one. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0902.2432v3-abstract-full').style.display = 'none'; document.getElementById('0902.2432v3-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 May, 2009; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 February, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2009. </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">26 pages, 11 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/0808.3880">arXiv:0808.3880</a> <span> [<a href="https://arxiv.org/pdf/0808.3880">pdf</a>, <a href="https://arxiv.org/ps/0808.3880">ps</a>, <a href="https://arxiv.org/format/0808.3880">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> The security of Ping-Pong protocol </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Tan%2C+J">Jian-Chuan Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="0808.3880v1-abstract-short" style="display: inline;"> Ping-Pong protocol is a type of quantum key distribution which makes use of two entangled photons in the EPR state. Its security is based on the randomization of the operations that Alice performs on the travel photon (qubit), and on the anti-correlation between the two photons in the EPR state. In this paper, we study the security of this protocol against some known quantum attacks, and present… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0808.3880v1-abstract-full').style.display = 'inline'; document.getElementById('0808.3880v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0808.3880v1-abstract-full" style="display: none;"> Ping-Pong protocol is a type of quantum key distribution which makes use of two entangled photons in the EPR state. Its security is based on the randomization of the operations that Alice performs on the travel photon (qubit), and on the anti-correlation between the two photons in the EPR state. In this paper, we study the security of this protocol against some known quantum attacks, and present a scheme that may enhance its security to some degree. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0808.3880v1-abstract-full').style.display = 'none'; document.getElementById('0808.3880v1-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 August, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2008. </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, 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/0805.3951">arXiv:0805.3951</a> <span> [<a href="https://arxiv.org/pdf/0805.3951">pdf</a>, <a href="https://arxiv.org/ps/0805.3951">ps</a>, <a href="https://arxiv.org/format/0805.3951">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1016/j.physleta.2008.12.032">10.1016/j.physleta.2008.12.032 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum strategy in moving frames </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Tan%2C+J">Jian-Chuan Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="0805.3951v1-abstract-short" style="display: inline;"> We investigate quantum strategy in moving frames by considering Prisoner's Dilemma and propose four thresholds of $纬$ for two players to determine their \textit{Nash Equilibria}. Specially, an interesting phenomenon appears in relativistic situation that the quantum feature of the game would be enhanced and diminished for different players whose particle's initial spin direction are respectively… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0805.3951v1-abstract-full').style.display = 'inline'; document.getElementById('0805.3951v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0805.3951v1-abstract-full" style="display: none;"> We investigate quantum strategy in moving frames by considering Prisoner's Dilemma and propose four thresholds of $纬$ for two players to determine their \textit{Nash Equilibria}. Specially, an interesting phenomenon appears in relativistic situation that the quantum feature of the game would be enhanced and diminished for different players whose particle's initial spin direction are respectively parallel and antiparallel to his/her movement direction, that is, for the former the quantum feature of the game is enhanced while for the latter the quantum feature would be diminished. Thus a classical latter could still maintain his/her strictly dominant strategy (classical strategy) even if the game itself is highly entangled. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0805.3951v1-abstract-full').style.display = 'none'; document.getElementById('0805.3951v1-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> 23 May, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2008. </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">11 pages, 10 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/0804.0714">arXiv:0804.0714</a> <span> [<a href="https://arxiv.org/pdf/0804.0714">pdf</a>, <a href="https://arxiv.org/ps/0804.0714">ps</a>, <a href="https://arxiv.org/format/0804.0714">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Combined local implementation of nonlocal operations using GHZ states </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+N+B">Ning Bo Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+A+M">An Min Wang</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="0804.0714v1-abstract-short" style="display: inline;"> We propose a protocol for local implementation of two consecutive nonlocal operations by three parters. It consumes one shared GHZ state in this protocol. We also demonstrate that these resources are sufficient and necessary to locally implement two consecutive CNOT operations. </span> <span class="abstract-full has-text-grey-dark mathjax" id="0804.0714v1-abstract-full" style="display: none;"> We propose a protocol for local implementation of two consecutive nonlocal operations by three parters. It consumes one shared GHZ state in this protocol. We also demonstrate that these resources are sufficient and necessary to locally implement two consecutive CNOT operations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0804.0714v1-abstract-full').style.display = 'none'; document.getElementById('0804.0714v1-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> 4 April, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2008. </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">8 pages 1 figue</span> </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=Wang%2C+A&start=50" 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