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</div> <div class="control"> <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=de+Andrade%2C+L&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=de+Andrade%2C+L&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=de+Andrade%2C+L&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/2502.04727">arXiv:2502.04727</a> <span> [<a href="https://arxiv.org/pdf/2502.04727">pdf</a>, <a href="https://arxiv.org/format/2502.04727">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey 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 - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> Is there a chiral dark dynamo in the universe induced by quantum correction, Nieh-Yan gravity and Barbero-Immirzi field? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Gao%2C+Z+F">Zhi Fu Gao</a>, <a href="/search/gr-qc?searchtype=author&query=Li%2C+B+P">Biao Peng Li</a>, <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="2502.04727v1-abstract-short" style="display: inline;"> Bombagcino investigated the role of Immirzi parameter when promoted to a field in Einstein-Cartan-Holst black hole and they found that the Immirzi field acts similar to the axion field, as both axial pseudo-vector and vectorial torsion trace appear to be expressed in terms of the 4-gradient of the Immirzi parameter. In this paper we introduced two important ingredients absent in the previous work:… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.04727v1-abstract-full').style.display = 'inline'; document.getElementById('2502.04727v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.04727v1-abstract-full" style="display: none;"> Bombagcino investigated the role of Immirzi parameter when promoted to a field in Einstein-Cartan-Holst black hole and they found that the Immirzi field acts similar to the axion field, as both axial pseudo-vector and vectorial torsion trace appear to be expressed in terms of the 4-gradient of the Immirzi parameter. In this paper we introduced two important ingredients absent in the previous work: the torsion mass, significant for the torsion detection the Large Hadron Collider, and the quantum correction proportional to the 4-divergent of torsion squared. Without the quantum correction, a simple analytical solution is obtained, while the more complicated field equations incorporating the BI field are obtained also analytically. The lower bound of quantum correction parameter is determined in terms of the torsion trace mass squared and axial torsion squared. Our findings reveal that in the late universe, the BI parameter approaches infinity restoring to the Einstein-Cartan theory in the early universe with the dynamical reduction of the Immirzi parameter to a constant BI parameter. Additionally, we derive analytical solutions for magnetic dynamos in the early universe, demonstrating that magnetic helicity is proportional to chiral chemical potential. A magnetic field at the QCD phase is found out of $10^{17}$ G, without quantum correction. Furthermore, from this dark magnetogenesis, we estimate light torsion with mass of the order of 1 TeV, An example of unitary preserved Lagrangian with axion as an Immirzi field is obtained. In the present universe we find a magnetic field strength of approximately $10^{-12}$ G which is quite close to the range found by Miniati at the QCD threshold, between $10^{-18}-10^{-15}$ G. Given that unitary violation on theoretical grounds may indicate new physics, exploring unitary violations in dark magnetogenesis could be particularly intriguing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.04727v1-abstract-full').style.display = 'none'; document.getElementById('2502.04727v1-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </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,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/2502.00419">arXiv:2502.00419</a> <span> [<a href="https://arxiv.org/pdf/2502.00419">pdf</a>, <a href="https://arxiv.org/ps/2502.00419">ps</a>, <a href="https://arxiv.org/format/2502.00419">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey 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 - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> Reheating chiral dynamos with spin-0 and massive spin-1 torsions via chiral asymmetry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Gao%2C+Z">Zhi-Fu Gao</a>, <a href="/search/gr-qc?searchtype=author&query=Li%2C+B">Biao-Peng Li</a>, <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="2502.00419v2-abstract-short" style="display: inline;"> Recently, Syderenko et al. (JCAP, 10: 018, 2016) investigated magnetogenesis and chiral asymmetry in the early hot universe. This study explores the impact of minimally coupling a constant torsion in their cosmological model, suggesting new chiral physics. Physically, this means that if torsion is right chiral, the difference between the number of right and left chiralities does not change. Moreov… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.00419v2-abstract-full').style.display = 'inline'; document.getElementById('2502.00419v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.00419v2-abstract-full" style="display: none;"> Recently, Syderenko et al. (JCAP, 10: 018, 2016) investigated magnetogenesis and chiral asymmetry in the early hot universe. This study explores the impact of minimally coupling a constant torsion in their cosmological model, suggesting new chiral physics. Physically, this means that if torsion is right chiral, the difference between the number of right and left chiralities does not change. Moreover, the decay of chiral asymmetry depends on torsion chirality. We solve the chiral torsionful dynamo equation for magnetic field seeds. Magnetic helical fields are considered important for chiral fermion asymmetry. Even in $(3+1)$ dimensional spacetime, torsion is highly suppressed beyond inflation (Eur Phys J C 82: 291, 2022). However, torsion of $1\,\mathrm{MeV}$ appears in the early universe. Equations for correlated magnetic field coefficients are solved in terms of torsion. Weak magnetic fields of the order of $10^{-42}$ Gauss are boosted by powerful torsionful dynamo amplification, generating a much stronger magnetic field of the order of $10^{-9}$ Gauss in the present universe. A galactic magnetic field of $10^{-6}$ Gauss in the present universe, with torsion of $10^{-15}$ Gauss, leads us to a galactic dynamo seed of $10^{-9}$ Gauss. We also discuss reheating dynamo regeneration of decaying cosmic magnetic fields during the hadronization era. The relation between the reheating contribution to e-folds and the connection between CMF and temperature squared allows us to obtain dynamo amplification in terms of N-folds of inflation. The main innovation of this work is the exploration of constant torsion in a cosmological model, revealing new chiral physics. This study offers a new perspective on the origin and evolution of magnetic fields in the early universe. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.00419v2-abstract-full').style.display = 'none'; document.getElementById('2502.00419v2-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </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,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/2412.16617">arXiv:2412.16617</a> <span> [<a href="https://arxiv.org/pdf/2412.16617">pdf</a>, <a href="https://arxiv.org/format/2412.16617">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> Dark photons and tachyonic instability induced by Barbero-Immirzi parameter and axion-torsion transmutation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Gao%2C+Z">Zhi-Fu Gao</a>, <a href="/search/gr-qc?searchtype=author&query=Li%2C+B">Biaopeng Li</a>, <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="2412.16617v1-abstract-short" style="display: inline;"> In this paper, we investigate Holst gravity by examining two distinct examples. The first example involves minimal coupling to torsion, while the second explores non-minimal coupling. The motivation for the first example stems from the recent work by Dombriz, which utilized a technique of imposing constraint constant coefficients to massive torsion in the model Lagrangian to determine parameters f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.16617v1-abstract-full').style.display = 'inline'; document.getElementById('2412.16617v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.16617v1-abstract-full" style="display: none;"> In this paper, we investigate Holst gravity by examining two distinct examples. The first example involves minimal coupling to torsion, while the second explores non-minimal coupling. The motivation for the first example stems from the recent work by Dombriz, which utilized a technique of imposing constraint constant coefficients to massive torsion in the model Lagrangian to determine parameters for the Einstein-Cartan-Holst gravity. We extend this methodology to investigate dark photons, where axial torsion transforms into axions.Interest in elucidating the abundance of dark photons within the framework of general relativity was sparked by Agrawal. Building on the work of Barman, who explored minimal coupling of massive torsion mediated by dark matter (DM) with light torsion on the order of 1.7 TeV, we have derived a Barbero-Immirzi (BI) parameter of approximately 0.775. This value falls within the range established by Panza et al. at TeV scales, specifically $0\le尾\le{1.185}$. This seems to our knowledge the first time BI parameter is induced by dark photons on a minimal EC gravity. Very recently, implications of findings of BI parameter in cosmological bounces has appeared in the literature. For a smaller BI parameter a higher torsion mass of 1.51 TeV is obtained. Nevertheless. this figure is still a signature of light torsion which can be compatible with light dark photon masses. Magnetic helicity instability of dark photons is investigated. Axion oscillation frequency is shown to depend on the BI parameter and the BI spectra is determined by an histogram. This study not only broadens the understanding of Holst gravity but also provides crucial insights into the interplay between torsion, dark photons, and axions in the cosmological context. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.16617v1-abstract-full').style.display = 'none'; document.getElementById('2412.16617v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">16 pages, 1 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/2412.05982">arXiv:2412.05982</a> <span> [<a href="https://arxiv.org/pdf/2412.05982">pdf</a>, <a href="https://arxiv.org/ps/2412.05982">ps</a>, <a href="https://arxiv.org/format/2412.05982">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> Axion-photon-mixing dark matter conversion mediated by torsion mass constrained by the Barbero-Immirzi parameter </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Gao%2C+Z">Zhi-Fu Gao</a>, <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">Luiz C. Garcia de Andrade</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="2412.05982v1-abstract-short" style="display: inline;"> In the Standard Model\,(SM) of particle physics, photon-torsion mixing is extended to include the Einstein-Cartan portal to dark-photon-axion-torsion mixing beyond the Standard Model\,(BSM), mediated by torsion. The Barbero-Immirzi(BI) parameter, of the order of $10^{-31}$, is more stringent than those obtained by Aliberti and Lambiase using matter-antimatter asymmetry. This paper presents the cou… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.05982v1-abstract-full').style.display = 'inline'; document.getElementById('2412.05982v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.05982v1-abstract-full" style="display: none;"> In the Standard Model\,(SM) of particle physics, photon-torsion mixing is extended to include the Einstein-Cartan portal to dark-photon-axion-torsion mixing beyond the Standard Model\,(BSM), mediated by torsion. The Barbero-Immirzi(BI) parameter, of the order of $10^{-31}$, is more stringent than those obtained by Aliberti and Lambiase using matter-antimatter asymmetry. This paper presents the coupling of the SM with dark matter\,(DM) axions, both mediated by torsion. We discuss tordions, the quanta of torsion, and the damping of propagating torsion. It is shown that with both kinds of vectorial torsion masses, equations from Einstein-Cartan-Holst gravity can be derived, which reduce to axionic photon equations where torsion appears only through its mass spectrum. Photon-axion conversions and axion mixing are found to depend on the BI parameter. This study demonstrates that when the spin-0 torsion mass is finite and Proca electrodynamics is not ghost-free, dark axion masses align with spin-0 torsion masses via axion-driven torsion and photon-torsion mixing. Our results provide innovative insights into Proca gravity models and the role of torsion in photon-axion conversion and dark matter dynamics, thereby offering a solid foundation for future research and new theoretical frameworks in quantum gravity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.05982v1-abstract-full').style.display = 'none'; document.getElementById('2412.05982v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">9 Pages, Submitted to Euro.Phys.J.C</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1604.01368">arXiv:1604.01368</a> <span> [<a href="https://arxiv.org/pdf/1604.01368">pdf</a>, <a href="https://arxiv.org/ps/1604.01368">ps</a>, <a href="https://arxiv.org/format/1604.01368">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> </div> </div> <p class="title is-5 mathjax"> Early Universe Dynamos from Neutrino Oscillations Induced by Torsion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</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="1604.01368v1-abstract-short" style="display: inline;"> Earlier de Sabbata and Gasperini have shown that neutrinos oscillation which gives them a mass can be induced by torsion. More recently Enqvist et al have shown that it is possible to use massive neutrinos BBN magnetic fields to seed galactic magnetic fields. Thus based on these previous investigations we present several examples of how obtaining cosmological magnetic seed fields as galactic magne… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.01368v1-abstract-full').style.display = 'inline'; document.getElementById('1604.01368v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1604.01368v1-abstract-full" style="display: none;"> Earlier de Sabbata and Gasperini have shown that neutrinos oscillation which gives them a mass can be induced by torsion. More recently Enqvist et al have shown that it is possible to use massive neutrinos BBN magnetic fields to seed galactic magnetic fields. Thus based on these previous investigations we present several examples of how obtaining cosmological magnetic seed fields as galactic magnetic fields from massive neutrino densities and also from the torsion obtained by Nitsch as $T\approx{10^{-24}s^{-1}}$ at the present day which yields magnetic seed field of the order of $B_{seed}\approx{10^{-12}G}$. In the case we use torsion derived from massive neutrinos given by $T_谓\approx{10^{-26}s^{-1}}$ one obtains in BBN time $t\approx{1s}$ with the primordial nucleosynthesis magnetic field given by $B_{BBN}\approx{10^{11}G}$ a relic magnetic field $B_{c}\approx{10^{39}G}$ which shows that the result obtained by Enqvist et al for the cosmological fields at the early universe. Galactic dynamo seed could be obtained from neutrinos at recombination. It is also shown that in the approximation of weak fields torsion can slow down the decay of magnetic fields which confirms previous results. At Planck era where the time is $t\sim{10^{-43}s}$ and $B_{Pl}\sim{10^{58}G}$ the use of formula with the strongest torsion $10^{-19}G$this yields $B_{seed}\sim{10^{-4}G}$ is a too strong field to warrant a galactic dynamo seed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.01368v1-abstract-full').style.display = 'none'; document.getElementById('1604.01368v1-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 April, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2016. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1501.00489">arXiv:1501.00489</a> <span> [<a href="https://arxiv.org/pdf/1501.00489">pdf</a>, <a href="https://arxiv.org/ps/1501.00489">ps</a>, <a href="https://arxiv.org/format/1501.00489">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> </div> </div> <p class="title is-5 mathjax"> Magnetogenesis from axion and dilaton electromagnetism in torsioned spacetime </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Andrade%2C+L+C+G">L. C. G. Andrade</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1501.00489v2-abstract-short" style="display: inline;"> Recently much controversy has been shed on BICEP 2 experiments for the concerning this validity or not and a possible set of new experiments to detect primordial inflation and gravitational waves. Since gravitational waves imply the existence of primordial magnetic fields in this context, C Bonvin, R Durrer and R Marteens [Phys Rev Lett (2014)] have tried to associate the presence of primordial ma… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.00489v2-abstract-full').style.display = 'inline'; document.getElementById('1501.00489v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1501.00489v2-abstract-full" style="display: none;"> Recently much controversy has been shed on BICEP 2 experiments for the concerning this validity or not and a possible set of new experiments to detect primordial inflation and gravitational waves. Since gravitational waves imply the existence of primordial magnetic fields in this context, C Bonvin, R Durrer and R Marteens [Phys Rev Lett (2014)] have tried to associate the presence of primordial magnetic fields to BICEP 2 by making use of CMB tensor modes. Here we show that by considering torsion dilatonic lagrangean one obtains cosmological magnetic fields of the order of $B\sim{10^{-10}G}$ which may seed galactic dynamos. Actually this new result came out of a mistake of a recent paper published by myself in JCAP (2014). These results are more in accordance with Bamba results [JCAP (2014)] in the context of teleparallel theory of gravity with Einstein's distant parallelism and torsion. These results also support Einstein-Cartan sort of theories of gravity from well-known recent data. Another example which supports the use of modified gravities with torsion to investigate magnetogenesis is the alternative exampleof using axions with transmutation into torsion to obtain cosmic magnetic seed bound of $10^{-12}G$.This coincides with the lower bound obtained by Barrow et al [Phys Rev D (2012)] in the interval of $10^{-20}G$ to $10^{-12}G$ in Friedmann universes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.00489v2-abstract-full').style.display = 'none'; document.getElementById('1501.00489v2-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 January, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 January, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">depto de fisica teorica, IF,UERJ, RJ Brasil</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1401.2587">arXiv:1401.2587</a> <span> [<a href="https://arxiv.org/pdf/1401.2587">pdf</a>, <a href="https://arxiv.org/ps/1401.2587">ps</a>, <a href="https://arxiv.org/format/1401.2587">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> </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/10.1088/1475-7516/2014/08/023">10.1088/1475-7516/2014/08/023 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Galactic dynamo seeds from non-superconducting spin-polarised strings </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="1401.2587v1-abstract-short" style="display: inline;"> Earlier Enqvist and Olesen have shown that formation of ferromagnetic planar walls in vacuum at GUT scales in comoving plasmas may generate a large scale magnetic field of $B_{now}\simeq{10^{-14}G}$. In this paper we show that starting from classical Einstein-Cartan-Maxwell strong gravity, a spin-polarised ferromagnetic cylinder gives rise to a cosmological magnetic field of the order… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1401.2587v1-abstract-full').style.display = 'inline'; document.getElementById('1401.2587v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1401.2587v1-abstract-full" style="display: none;"> Earlier Enqvist and Olesen have shown that formation of ferromagnetic planar walls in vacuum at GUT scales in comoving plasmas may generate a large scale magnetic field of $B_{now}\simeq{10^{-14}G}$. In this paper we show that starting from classical Einstein-Cartan-Maxwell strong gravity, a spin-polarised ferromagnetic cylinder gives rise to a cosmological magnetic field of the order $B_{now}\simeq{10^{-22}G}$. Vorticity of cylinder is used to obtain galactic magnetic fields. Magnetic fields up to $B\sim{10^{9}G}$ can be obtained from the spin density of the cylinder. If matching conditions are used cosmological magnetic fields of the order of $B\sim{10^{-16}R\frac{Gauss}{cm}}$ where $R$ is the radius of the cosmic strings. For a cosmic string with the radius of an hydrogen atom the cosmic magnetic field is $B\sim{10^{-32}Gauss}$ which is enough to seed galactic dynamos. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1401.2587v1-abstract-full').style.display = 'none'; document.getElementById('1401.2587v1-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 January, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">arXiv admin note: substantial text overlap with arXiv:gr-qc/0211072</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1307.0142">arXiv:1307.0142</a> <span> [<a href="https://arxiv.org/pdf/1307.0142">pdf</a>, <a href="https://arxiv.org/ps/1307.0142">ps</a>, <a href="https://arxiv.org/format/1307.0142">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> Stringent magnetic field limits from early universe dynamos cosmology with torsion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">Luiz Carlos Garcia de Andrade</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="1307.0142v1-abstract-short" style="display: inline;"> Earlier Bamba et al [JCAP (2012)] have obtained cosmological magnetic fields in teleparallel torsion theories of gravity that are not compatible with galactic dynamos. This result agrees with previous ones obtained by the author which shows [Phys Lett B (2012)] that anti-dynamo generalised theorem to torsion theories forbides such kind of dynamos to explain galactic magnetic fields of the order of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1307.0142v1-abstract-full').style.display = 'inline'; document.getElementById('1307.0142v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1307.0142v1-abstract-full" style="display: none;"> Earlier Bamba et al [JCAP (2012)] have obtained cosmological magnetic fields in teleparallel torsion theories of gravity that are not compatible with galactic dynamos. This result agrees with previous ones obtained by the author which shows [Phys Lett B (2012)] that anti-dynamo generalised theorem to torsion theories forbides such kind of dynamos to explain galactic magnetic fields of the order of $渭$G. More recently the author has suggested [IJAA (2012)] that a sort of Biermann battery could be obtained in torsioned cosmology. Nevertheless in this paper we show that this can be a particular result, since the second author did not took into account mean field dynamo equations in torsion field background. Actually it is shown that amplification or not of the magnetic field depends upon handness sign of the torsion field vector. It is shown that density fluctuations of spin-torsion density implies also a possibility of amplification of the cosmic magnetic fields. From WMAP data it is possible to estimate the spin-torsion fluctuation as $10^{-6}$ which represents an order of magnitude lower than the matter density. By making use of the gravitational couling of type $RF^{2}$ one obtains $10^{37}G$ for the Planck era magnetic field, which is a much more stringent limit than the ones obtained earlier. The magnetic field obtained today is $10^{-23}G$ is obtained which is able to seed galactic dynamos. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1307.0142v1-abstract-full').style.display = 'none'; document.getElementById('1307.0142v1-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 June, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">Dept of theoretical physics, UERJ, Brasil</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1110.3112">arXiv:1110.3112</a> <span> [<a href="https://arxiv.org/pdf/1110.3112">pdf</a>, <a href="https://arxiv.org/ps/1110.3112">ps</a>, <a href="https://arxiv.org/format/1110.3112">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="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> </div> </div> <p class="title is-5 mathjax"> Decoupling between torsion and magnetic fields in bouncing cosmology and galactic dynamo seeds </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</a>, <a href="/search/gr-qc?searchtype=author&query=Ferrandez%2C+A">Angel Ferrandez</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="1110.3112v1-abstract-short" style="display: inline;"> Recently Salim et al [JCAP (2007)], have shown that galactic dynamo seeds can be possibly attainable in bouncing cosmological models with QED Lagrangeans. In this paper we generalise their result by include torsion of spacetime in bouncing cosmology. It is shown that by considering a semi-minimal photon-torsion coupling and a Lagrangean of the type $RF^{2}$ it is possible to find a fast decoupling… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1110.3112v1-abstract-full').style.display = 'inline'; document.getElementById('1110.3112v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1110.3112v1-abstract-full" style="display: none;"> Recently Salim et al [JCAP (2007)], have shown that galactic dynamo seeds can be possibly attainable in bouncing cosmological models with QED Lagrangeans. In this paper we generalise their result by include torsion of spacetime in bouncing cosmology. It is shown that by considering a semi-minimal photon-torsion coupling and a Lagrangean of the type $RF^{2}$ it is possible to find a fast decoupling between magnetic and torsion fields in the contracting phases of the universe. Besides torsion field decays as $K\sim{a^{2/3}}$ while the magnetic field grows as $B\sim{a^{-5.5}}$ thus explaining the fast decoupling between the two fields. It is expected that at some point of the contracting phase the amplification of the magnetic field may give rise to a enough strong magnetic field to seed a galactic dynamo. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1110.3112v1-abstract-full').style.display = 'none'; document.getElementById('1110.3112v1-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 October, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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 Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1110.3111">arXiv:1110.3111</a> <span> [<a href="https://arxiv.org/pdf/1110.3111">pdf</a>, <a href="https://arxiv.org/ps/1110.3111">ps</a>, <a href="https://arxiv.org/format/1110.3111">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> Cosmological magnetic helicity and birefrigence from primordial torsion in Lorentz violation theories </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+G">L Garcia de Andrade</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="1110.3111v1-abstract-short" style="display: inline;"> Cosmological magnetic helicity has been thought to be a fundamental agent for magnetic field amplification in the universe. More recently Semikoz and Sokoloff [Phys Rev Lett 92 (2004): 131.301.] showed that the weakness of the seed fields did not necessarily imply the weakness of magnetic cosmological helicity. In this paper we present a derivation of dynamo equation based upon the flat torsion ph… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1110.3111v1-abstract-full').style.display = 'inline'; document.getElementById('1110.3111v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1110.3111v1-abstract-full" style="display: none;"> Cosmological magnetic helicity has been thought to be a fundamental agent for magnetic field amplification in the universe. More recently Semikoz and Sokoloff [Phys Rev Lett 92 (2004): 131.301.] showed that the weakness of the seed fields did not necessarily imply the weakness of magnetic cosmological helicity. In this paper we present a derivation of dynamo equation based upon the flat torsion photon non-minimal coupling through Riemann-Cartan spacetime. From this derivation one computes the necessary conditions for a flat torsion field to generate a galactic dynamo seed, from the cosmological magnetic helicity. A peculiar feature of this dynamo equation is that the resistivity depends upon the Ricci scalar curvature. This feature is also present in turbulent dynamo models. Here the electrical effective conductivity is obtained by making use of flat torsion modes of a $R(螕)F^{2}$ Lagrangean where R refers to the Ricci-Cartan spacetime. Power spectrum of the magnetic field is also computed. Lorentz violation appears naturally from birefrigence of photons semi-minimally coupled to torsion. Though Dobado and Maroto [Mod Phys Lett A 12: 3003 (1997)] have previously investigated the role of primordial torsion in the anisotropy of light propagation they made it using the fermionic sector of the QED Lagrangean while we obtained similar results using the photonic sector. They also used the pseudo-trace of torsion while we here work out with the torsion trace itself. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1110.3111v1-abstract-full').style.display = 'none'; document.getElementById('1110.3111v1-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 October, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">departamento de fisica teorica-UERJ-Rio de Janeiro-Brasil</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1105.1573">arXiv:1105.1573</a> <span> [<a href="https://arxiv.org/pdf/1105.1573">pdf</a>, <a href="https://arxiv.org/ps/1105.1573">ps</a>, <a href="https://arxiv.org/format/1105.1573">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</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/S0217732312500599">10.1142/S0217732312500599 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Faraday rotation and primordial magnetic field constraints on Ultraviolet Lorentz violation with spacetime torsion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L C Garcia de Andrade</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="1105.1573v1-abstract-short" style="display: inline;"> Recently Kahniashivili et al (2006) presented a unified treatment for ultraviolet Lorentz violation (LV) testing through electromagnetic wave propagation in magnetised plasmas, based on dispersion and rotation measured data. Based on the fact discovered recently by Kostelecky et al (2008), that LV may place constraints on spacetime torsion, in this paper it is shown that on the limit of very low f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1105.1573v1-abstract-full').style.display = 'inline'; document.getElementById('1105.1573v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1105.1573v1-abstract-full" style="display: none;"> Recently Kahniashivili et al (2006) presented a unified treatment for ultraviolet Lorentz violation (LV) testing through electromagnetic wave propagation in magnetised plasmas, based on dispersion and rotation measured data. Based on the fact discovered recently by Kostelecky et al (2008), that LV may place constraints on spacetime torsion, in this paper it is shown that on the limit of very low frequency torsion waves, it is possible to constraint torsion from Faraday rotation and CMB on a similar fashion as Minkowski spacetime plus torsion. Here the Maxwells modified equations are obtained by a perturbative method introduced by de Sabbata and Gasperini (1981). Torsion is constraint to $Q_{CMB}\approx{10^{-18}GeV}$ which is not so stringent as the $10^{-31}GeV$ obtained by Kostelecky et al. However, Gamma Ray Bursts (GBRs) may lead to the more string value obtined by Kostelecky et al. Another interesting constraint on torsion is shown to be placed by galactic dynamo seed magnetic fields. For torsion effects be compatible with the galactic dynamo seeds one obtains a torsion constraint of $10^{-33}GeV$ which is two orders of magnitude more stringent that the above Kostelecky et al limit. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1105.1573v1-abstract-full').style.display = 'none'; document.getElementById('1105.1573v1-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 May, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">Departamento de fisica teorica-Universidade do Estado do Rio de Janeiro-UERJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1007.1803">arXiv:1007.1803</a> <span> [<a href="https://arxiv.org/pdf/1007.1803">pdf</a>, <a href="https://arxiv.org/ps/1007.1803">ps</a>, <a href="https://arxiv.org/format/1007.1803">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="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> </div> <p class="title is-5 mathjax"> Primordial magnetic fields of non-minimal photon-torsion axial coupling origin </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</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="1007.1803v1-abstract-short" style="display: inline;"> Dynamo action is shown to be induced from homogeneous non-minimal photon-torsion axial coupling in the quantum electrodynamics (QED) framework in Riemann flat spacetime contortion decays. The geometrical optics in Riemann-Cartan spacetime is considering and a plane wave expansion of the electromagnetic vector potential is considered leading to a set of the equations for the ray congruence. Since w… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1007.1803v1-abstract-full').style.display = 'inline'; document.getElementById('1007.1803v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1007.1803v1-abstract-full" style="display: none;"> Dynamo action is shown to be induced from homogeneous non-minimal photon-torsion axial coupling in the quantum electrodynamics (QED) framework in Riemann flat spacetime contortion decays. The geometrical optics in Riemann-Cartan spacetime is considering and a plane wave expansion of the electromagnetic vector potential is considered leading to a set of the equations for the ray congruence. Since we are interested mainly on the torsion effects in this first report we just consider the Riemann-flat case composed of the Minkowskian spacetime with torsion. It is also shown that in torsionic de Sitter background the vacuum polarisation does alter the propagation of individual photons, an effect which is absent in Riemannian spaces. It is shown that the cosmological torsion background inhomogeneities induce Lorentz violation and massive photon modes in this QED. Magnetic dynamos in this torsioned spacetime electrodynamics are simpler obtained in Fourier space than the cosmic ones, previously obtained by Bassett et al Phys Rev D, in Friedmann universe. By deriving plasma dispersion for linear electrodynamics in Riemann Cartan spacetime, dynamo action seems to be possible for plasma frequencies in some polarizations. The important cosmic magnetic field problem of breaking conformal flatness is naturally solved here since the photon torsion coupling breaks conformal flatness. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1007.1803v1-abstract-full').style.display = 'none'; document.getElementById('1007.1803v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 July, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">depto de fisica teorica, if uerj, state rio de janeiro university</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0912.2461">arXiv:0912.2461</a> <span> [<a href="https://arxiv.org/pdf/0912.2461">pdf</a>, <a href="https://arxiv.org/ps/0912.2461">ps</a>, <a href="https://arxiv.org/format/0912.2461">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> </div> </div> <p class="title is-5 mathjax"> Mean-field cosmological dynamo curvature vs turbulence spectrum in Riemannian space </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+G">L Garcia de Andrade</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="0912.2461v3-abstract-short" style="display: inline;"> Previous attempts for building a cosmic dynamo including preheating in inflationary universes [Bassett et al Phys Rev (2001)] has not included mean field dynamos. Here, a mean field dynamo in cosmic scales on a Riemannian spatial cosmological section background, is set up. When magnetic fields and flow velocities are parallel propagated along the Riemannian space dynamo action is obtained. Turbu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0912.2461v3-abstract-full').style.display = 'inline'; document.getElementById('0912.2461v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0912.2461v3-abstract-full" style="display: none;"> Previous attempts for building a cosmic dynamo including preheating in inflationary universes [Bassett et al Phys Rev (2001)] has not included mean field dynamos. Here, a mean field dynamo in cosmic scales on a Riemannian spatial cosmological section background, is set up. When magnetic fields and flow velocities are parallel propagated along the Riemannian space dynamo action is obtained. Turbulent diffusivity $尾$ is coupled with the Ricci magnetic curvature, as in Marklund and Clarkson [MNRAS (2005)], GR-MHD dynamo equation. Mean electric field possesses an extra term due to Ricci tensor coupling with magnetic vector potential in Ohm's law. Goedel universe induces a mean field dynamo growth rate $纬=2蠅^{2}尾$. In this frame kinetic helicity vanishes. By considering a universe vorticity, $蠅\approx{10^{-16}s^{-1}}$ for galactic dynamos, thus $纬=2.10^{-32}尾$, and since $尾\approx{10^{26}cm^{2}s^{-1}}$, the growth rate $纬\approx{10^{-6}s^{-1}}$. In non-comoving the magnetic field is expressed as $B\approx{\sqrt{\frac{2尾}纬}{\times}10^{-6}G}\approx{10^{10}G}$ a magnetic field found in the nucleosynthesis era. The Ricci scalar turbulence spectrum of the cosmic dynamos is computed from the GR-MHD dynamo equation. By analyzing the Fourier modes of the Ricci scalar, one shows that the energy spectrum of the curvature turbulent dynamo is similar to the Kolmogorov spectrum. Similar enhancements of turbulence in Friedmann cosmology have been obtained by Brandenburg et al [Phys Rev D (1997)]. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0912.2461v3-abstract-full').style.display = 'none'; document.getElementById('0912.2461v3-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 December, 2009; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 December, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">Departamento de Fisica Teorica-IF-UERJ-Rio-RJ-Brasil</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0910.4816">arXiv:0910.4816</a> <span> [<a href="https://arxiv.org/pdf/0910.4816">pdf</a>, <a href="https://arxiv.org/ps/0910.4816">ps</a>, <a href="https://arxiv.org/format/0910.4816">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> </div> </div> <p class="title is-5 mathjax"> Slow dynamos in Lorentz tori Anti-de Sitter spacetime embedded in Riemann 2D-space </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</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="0910.4816v1-abstract-short" style="display: inline;"> Earlier Chicone, Latushkin and Montgomery-Smith [Comm Math Phys (1997)] have shown that a fast dynamo in compact two-dimensional manifold can be supported as long as its Riemannian curvature be negative. Recently Klebanov and Maldacena [Phys Today (2008)] showed that a similar flat spacetime embedding of a 2D negative Riemannian hyperbolic embedding in 2+1-D space-time, is achieved by a coordina… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0910.4816v1-abstract-full').style.display = 'inline'; document.getElementById('0910.4816v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0910.4816v1-abstract-full" style="display: none;"> Earlier Chicone, Latushkin and Montgomery-Smith [Comm Math Phys (1997)] have shown that a fast dynamo in compact two-dimensional manifold can be supported as long as its Riemannian curvature be negative. Recently Klebanov and Maldacena [Phys Today (2008)] showed that a similar flat spacetime embedding of a 2D negative Riemannian hyperbolic embedding in 2+1-D space-time, is achieved by a coordinate transformation. This embedding is used here to obtain a flat spacetime embedding of a slow dynamo in Riemannian 2D compact manifold of negative constant curvature. In is shown that a slow dynamo appears in anti-de Sitter space (AdS) Lorentz tori. This is in agreement with Bassett et al [Phys Rev D (2001)] cosmic dynamo where suppression of resonance by universe expansion slow dynamo action in comparison to preheating phases. Other example of flat embeddings, which keeps some resamblance with AdS slow dynamo, is given by the embedding of Moebius strip [Shukurov, Stepanov, Sokoloff, PRE (2008)] in the laboratory. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0910.4816v1-abstract-full').style.display = 'none'; document.getElementById('0910.4816v1-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 October, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2009. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0906.2044">arXiv:0906.2044</a> <span> [<a href="https://arxiv.org/pdf/0906.2044">pdf</a>, <a href="https://arxiv.org/ps/0906.2044">ps</a>, <a href="https://arxiv.org/format/0906.2044">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> </div> </div> <p class="title is-5 mathjax"> Rotation and helicity as dynamo generators in idealized plasma cosmologies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</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="0906.2044v4-abstract-short" style="display: inline;"> Recently Kleides et al [IJMPA \textbf{11}, 1697 (2008)] found a growing rate for magnetic fields in ideal plasma cosmologies by making use of general relativistic Friedmann model. This growth rate of $\frac{未B}{B}\sim{{(\frac{t}{t_{H}})}^{1/4}}$ indicates the presence of a slow dynamo in the universe. More recently Hasseein [Phys Plasmas (2009)] have also investigate Beltrami magnetic fields in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0906.2044v4-abstract-full').style.display = 'inline'; document.getElementById('0906.2044v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0906.2044v4-abstract-full" style="display: none;"> Recently Kleides et al [IJMPA \textbf{11}, 1697 (2008)] found a growing rate for magnetic fields in ideal plasma cosmologies by making use of general relativistic Friedmann model. This growth rate of $\frac{未B}{B}\sim{{(\frac{t}{t_{H}})}^{1/4}}$ indicates the presence of a slow dynamo in the universe. More recently Hasseein [Phys Plasmas (2009)] have also investigate Beltrami magnetic fields in plasma universe. Here general relativistic(GR) MHD dynamo equation, recently given by Clarkson and Marklund [Monthly Not Roy Astr Soc (2005)] is used to investigate the relation between collapsing of the isotropic universe and dynamo action in ideal and dissipative cosmologies. Dynamo action can be supported in these phases as long as the kinetic helicity overcomes universe diffusion effects. A cosmological Beltrami flow in 3D shows that helicities may act constructively on gravitational collapse and enhance dynamo action. A slow dynamo action is found in the static Einstein universe also filled with a Beltrami flow. A rotating, shear-free Bianchi type-IX universe, is obtained, by magnetically perturbing the Einstein static model inducing slow dynamos in the model. Magnetic field growth of $B\approx{t}$, which is stronger than Harrison estimate of $B\approx{t^{4/5}}$ is obtained. CMB limits on the expansion, global rotation and slow dynamos are given and a less slower dynamo than the one obtained by Kleides et al, is found with $\frac{未B}{B}\sim{|螛|t}$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0906.2044v4-abstract-full').style.display = 'none'; document.getElementById('0906.2044v4-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 July, 2009; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 June, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">Department of theoretical physics-UERJ-RJ-Brasil</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0905.2001">arXiv:0905.2001</a> <span> [<a href="https://arxiv.org/pdf/0905.2001">pdf</a>, <a href="https://arxiv.org/ps/0905.2001">ps</a>, <a href="https://arxiv.org/format/0905.2001">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> </div> </div> <p class="title is-5 mathjax"> Cosmic dynamo analogue and decay of magnetic fields in 3D Ricci flows </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</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="0905.2001v1-abstract-short" style="display: inline;"> Magnetic curvature effects, investigated by Barrow and Tsagas (BT) [Phys Rev D \textbf{77},(2008)],as a mechanism for magnetic field decay in open Friedmann universes ($螞<0$), are applied to dynamo geometric Ricci flows in 3D curved substrate in laboratory. By simple derivation, a covariant three-dimensional magnetic self-induced equation, presence of these curvature effects, indicates that de S… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0905.2001v1-abstract-full').style.display = 'inline'; document.getElementById('0905.2001v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0905.2001v1-abstract-full" style="display: none;"> Magnetic curvature effects, investigated by Barrow and Tsagas (BT) [Phys Rev D \textbf{77},(2008)],as a mechanism for magnetic field decay in open Friedmann universes ($螞<0$), are applied to dynamo geometric Ricci flows in 3D curved substrate in laboratory. By simple derivation, a covariant three-dimensional magnetic self-induced equation, presence of these curvature effects, indicates that de Sitter cosmological constant ($螞\ge{0}$), leads to enhancement in the fast kinematic dynamo action which adds to stretching of plasma flows. From the magnetic growth rate, the strong shear case, anti-de Sitter case ($螞<0$) BT magnetic decaying fields are possible while for weak shear, fast dynamos are possible. The self-induced equation in Ricci flows is similar to the equation derived by BT in $(3+1)$-spacetime continuum. Lyapunov-de Sitter metric is obtained from Ricci flow eigenvalue problem. In de Sitter analogue there is a decay rate of $纬\approx{-螞}\approx{-10^{-35}s^{-2}}$ from corresponding cosmological constant $螞$, showing that, even in the dynamo case, magnetic field growth is slower than de Sitter inflation, which strongly supports to BT result. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0905.2001v1-abstract-full').style.display = 'none'; document.getElementById('0905.2001v1-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 May, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">Departamento de fisica Teorica-IF-Universidade do Estado do Rio de Janeiro-Brasil</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0808.3120">arXiv:0808.3120</a> <span> [<a href="https://arxiv.org/pdf/0808.3120">pdf</a>, <a href="https://arxiv.org/ps/0808.3120">ps</a>, <a href="https://arxiv.org/format/0808.3120">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> </div> </div> <p class="title is-5 mathjax"> Acoustic black hole evaporation as plasma diffusion phenomena </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</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="0808.3120v1-abstract-short" style="display: inline;"> Acoustic analogues of Kerr black hole in plasmas are considered, by taking for granted the existence of acoustic ion waves in plasmas. An effective black holes (BH) in curved Riemannian spacetime in a random walk plasmas is endowed with a naked singularity, when plasmas are in the lowest diffusion mode. The plasma particle diffusion is encoded in the effective metric. The diffusive solution has… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0808.3120v1-abstract-full').style.display = 'inline'; document.getElementById('0808.3120v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0808.3120v1-abstract-full" style="display: none;"> Acoustic analogues of Kerr black hole in plasmas are considered, by taking for granted the existence of acoustic ion waves in plasmas. An effective black holes (BH) in curved Riemannian spacetime in a random walk plasmas is endowed with a naked singularity, when plasmas are in the lowest diffusion mode. The plasma particle diffusion is encoded in the effective metric. The diffusive solution has a horizon when the plasma flow reaches the sound velocity in the medium and a shock wave is obtained inside the slab. The sonic black hole curved Riemannian metric is also found in terms of particle number density in plasmas. The sonic BH singularity is found at the center of the plasma diffusive slab from the study of the Ricci curvature scalar for constant diffusion coefficient. It is suggested and shown that the Hawking temperature is proportional to the plasma Kelvin temperature through diffusion coefficient dependence to this temperature. Therefore Unruh sonic or dumb BH is shown to have a relation between Hawking and plasma diffusive temperatures. BH evaporation is analogous to the diffusive phenomena in plasmas, since in both cases Hawking temperature is inversely proportional to mass. It is shown that Hawking analogue temperature of a plasma torus is $T_{H}(torus)\approx{10^{-4}K}$ which is much higher than the gravitational Hawking temperature of a one solar mass BH, ${T_{H}}^{GR}\approx{10^{-8}K}$, but still very small for being detectable in plasma laboratories. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0808.3120v1-abstract-full').style.display = 'none'; document.getElementById('0808.3120v1-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, 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">Dept fisica teorica-UERJ-Brasil</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0808.2272">arXiv:0808.2272</a> <span> [<a href="https://arxiv.org/pdf/0808.2272">pdf</a>, <a href="https://arxiv.org/ps/0808.2272">ps</a>, <a href="https://arxiv.org/format/0808.2272">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> </div> </div> <p class="title is-5 mathjax"> Effective black holes from non-Riemannian vortex acoustics in ABC flows </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</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="0808.2272v1-abstract-short" style="display: inline;"> Since Alfven, dynamo and sound waves and the existence of general relativistic black holes are well stablished in plasma physics, this provides enough motivation to investigate the presence of acoustic black-hole effective metric of analogue Einstein's gravity in dynamo flows. From nonlinear dynamo equations, one obtains a non-homogeneous wave equation where it is shown that the non-homogeneous… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0808.2272v1-abstract-full').style.display = 'inline'; document.getElementById('0808.2272v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0808.2272v1-abstract-full" style="display: none;"> Since Alfven, dynamo and sound waves and the existence of general relativistic black holes are well stablished in plasma physics, this provides enough motivation to investigate the presence of acoustic black-hole effective metric of analogue Einstein's gravity in dynamo flows. From nonlinear dynamo equations, one obtains a non-homogeneous wave equation where it is shown that the non-homogeneous factor is proportional to time evolution of the compressibility factor. In the Navier-Stokes case for a finite Reynolds number the acoustic black-holes also exists on the stretching plasma flows. In the magnetostatic case the dynamo is marginal. Analog models are usually applied to a superfluid analog spacetime, instead of the plasma setting used here. A coupled nonlinear plasma flow solution is found for the dynamo equation where the effective black hole solution of the scalar effective equation yields an imaginary part of the growth of magnetic field. Therefore though the real part of the growth rate of the magnetic field is negative or null, since there is a temporal oscillation in magnetic field, the solution represents a slow dynamo. Thus acoustic black holes are shown to definitely contribute to dynamo action of the effective plasma spacetime. It is suggested that a fast dynamo effective spacetime may also contain an acoustic black hole. I the case of planar waves the effective metric can be cast in Kerr-Schild spacetime form. The Killing symmetries are explicitly given in this metric and the growth of dynamo waves. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0808.2272v1-abstract-full').style.display = 'none'; document.getElementById('0808.2272v1-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 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">Dept Fisica Teorica-IF-UERJ-Brasil</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0808.2271">arXiv:0808.2271</a> <span> [<a href="https://arxiv.org/pdf/0808.2271">pdf</a>, <a href="https://arxiv.org/ps/0808.2271">ps</a>, <a href="https://arxiv.org/format/0808.2271">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> </div> </div> <p class="title is-5 mathjax"> Kerr-Schild Riemannian acoustic black holes in dynamo plasma laboratory </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</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="0808.2271v1-abstract-short" style="display: inline;"> Since Alfven, dynamo and sound waves and the existence of general relativistic black holes are well stablished in plasma physics, this provides enough motivation to investigate the presence of acoustic black-hole effective metric of analogue Einstein's gravity in dynamo flows. From nonlinear dynamo equations, one obtains a non-homogeneous wave equation where it is shown that the non-homogeneous… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0808.2271v1-abstract-full').style.display = 'inline'; document.getElementById('0808.2271v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0808.2271v1-abstract-full" style="display: none;"> Since Alfven, dynamo and sound waves and the existence of general relativistic black holes are well stablished in plasma physics, this provides enough motivation to investigate the presence of acoustic black-hole effective metric of analogue Einstein's gravity in dynamo flows. From nonlinear dynamo equations, one obtains a non-homogeneous wave equation where it is shown that the non-homogeneous factor is proportional to time evolution of the compressibility factor. In the Navier-Stokes case for a finite Reynolds number the acoustic black-holes also exists on the stretching plasma flows. In the magnetostatic case the dynamo is marginal. Analog models are usually applied to a superfluid analog spacetime, instead of the plasma setting used here. A coupled nonlinear plasma flow solution is found for the dynamo equation where the effective black hole solution of the scalar effective equation yields an imaginary part of the growth of magnetic field. Therefore though the real part of the growth rate of the magnetic field is negative or null, since there is a temporal oscillation in magnetic field, the solution represents a slow dynamo. Thus acoustic black holes are shown to definitely contribute to dynamo action of the effective plasma spacetime. It is suggested that a fast dynamo effective spacetime may also contain an acoustic black hole. I the case of planar waves the effective metric can be cast in Kerr-Schild spacetime form. The Killing symmetries are explicitly given in this metric and the growth of dynamo waves. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0808.2271v1-abstract-full').style.display = 'none'; document.getElementById('0808.2271v1-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 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">Departamento de fisica teorica-if-uerj-Brasil</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0707.1734">arXiv:0707.1734</a> <span> [<a href="https://arxiv.org/pdf/0707.1734">pdf</a>, <a href="https://arxiv.org/ps/0707.1734">ps</a>, <a href="https://arxiv.org/format/0707.1734">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> </div> </div> <p class="title is-5 mathjax"> Kinematic fast cosmic dynamos in non-inflationary phases of ellipsoidal universe </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="0707.1734v1-abstract-short" style="display: inline;"> Cosmic kinematic fast dynamo is found in non-inflationary phases of an ellipsoidal anisotropic cosmological metric background solution of Einstein field equations of general relativity. The magnetic field is amplified inside the universe and spatially periodically. A finite resistivity is assumed, and a nonsingular flow velocity is aligned with the magnetic field which is orthogonal to a plane w… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0707.1734v1-abstract-full').style.display = 'inline'; document.getElementById('0707.1734v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0707.1734v1-abstract-full" style="display: none;"> Cosmic kinematic fast dynamo is found in non-inflationary phases of an ellipsoidal anisotropic cosmological metric background solution of Einstein field equations of general relativity. The magnetic field is amplified inside the universe and spatially periodically. A finite resistivity is assumed, and a nonsingular flow velocity is aligned with the magnetic field which is orthogonal to a plane which is analog to a galactic plane in astrophysics. Magnetic field components is stretched along the z-direction and a cosmic dynamo is created in the spirit of Zeldovich stretch, twist and fold (STF) dynamo generation mechanism. In the inflationary phase of the planar symmetric universe, the primordial magnetic field decays and the galactic plane expands as a de Sitter $(2+1)-spacetime$ and the eccentricity of the ellipsoidal universe, tends to vanish with inflation. We may conclude that, as far as the present model is concerned, anti-dynamos are obtained in inflationary phases. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0707.1734v1-abstract-full').style.display = 'none'; document.getElementById('0707.1734v1-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 July, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2007. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/physics/0703143">arXiv:physics/0703143</a> <span> [<a href="https://arxiv.org/pdf/physics/0703143">pdf</a>, <a href="https://arxiv.org/ps/physics/0703143">ps</a>, <a href="https://arxiv.org/format/physics/0703143">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Fluid Dynamics">physics.flu-dyn</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> <span class="tag is-small is-grey 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="Differential Geometry">math.DG</span> </div> </div> <p class="title is-5 mathjax"> An example of anti-dynamo conformal Arnold metric </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</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="physics/0703143v1-abstract-short" style="display: inline;"> A 3D metric conformally related to Arnold cat fast dynamo metric: ${ds_{A}}^{2}=e^{-位z}dp^{2}+e^{位z}dq^{2}+dz^{2}$ is shown to present a behaviour of non-dynamos where the magnetic field exponentially decay in time. The Riemann-Christoffel connection and Riemann curvature tensor for the Arnold and its conformal counterpart are computed. The curvature decay as z-coordinates increases without boun… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('physics/0703143v1-abstract-full').style.display = 'inline'; document.getElementById('physics/0703143v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="physics/0703143v1-abstract-full" style="display: none;"> A 3D metric conformally related to Arnold cat fast dynamo metric: ${ds_{A}}^{2}=e^{-位z}dp^{2}+e^{位z}dq^{2}+dz^{2}$ is shown to present a behaviour of non-dynamos where the magnetic field exponentially decay in time. The Riemann-Christoffel connection and Riemann curvature tensor for the Arnold and its conformal counterpart are computed. The curvature decay as z-coordinates increases without bounds. Some of the Riemann curvature components such as $R_{pzpz}$ also undergoes dissipation while component $R_{qzqz}$ increases without bounds. The remaining curvature component $R_{pqpq}$ is constant on the torus surface. The Riemann curvature invariant $K^{2}=R_{ijkl}R^{ijkl}$ is found to be 0.155 for the $位=0.75$. A simple solution of Killing equations for Arnold metric yields a stretch Killing vector along one direction and compressed along other direction in order that the modulus of the Killing vector is not constant along the flow. The flow is shown to be untwisted. The stability of the two metrics are found by examining the sign of their curvature tensor components. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('physics/0703143v1-abstract-full').style.display = 'none'; document.getElementById('physics/0703143v1-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 March, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2007. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/physics/0703014">arXiv:physics/0703014</a> <span> [<a href="https://arxiv.org/pdf/physics/0703014">pdf</a>, <a href="https://arxiv.org/ps/physics/0703014">ps</a>, <a href="https://arxiv.org/format/physics/0703014">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> <span class="tag is-small is-grey 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="Differential Geometry">math.DG</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Fluid Dynamics">physics.flu-dyn</span> </div> </div> <p class="title is-5 mathjax"> Plasma metric singularities in helical devices and tearing instabilities in tokamaks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</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="physics/0703014v1-abstract-short" style="display: inline;"> Plasma toroidal metric singularities in helical devices and tokamaks, giving rise to magnetic surfaces inside the plasma devices are investigated in two cases. In the first we consider the case of a rotational plasma on an helical device with circular cross-section and dissipation. In this case singularities are shown to place a Ricci scalar curvature bound on the radius of the surface where the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('physics/0703014v1-abstract-full').style.display = 'inline'; document.getElementById('physics/0703014v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="physics/0703014v1-abstract-full" style="display: none;"> Plasma toroidal metric singularities in helical devices and tokamaks, giving rise to magnetic surfaces inside the plasma devices are investigated in two cases. In the first we consider the case of a rotational plasma on an helical device with circular cross-section and dissipation. In this case singularities are shown to place a Ricci scalar curvature bound on the radius of the surface where the Ricci scalar is the contraction of the constant Riemannian curvature tensor of magnetic surfaces. An upper bound on the initial magnetic field in terms of the Ricci scalar is obtained. This last bound may be useful in the engineering construction of plasma devices in laboratories. The normal poloidal drift velocity is also computed. In the second case a toroidal metric is used to show that there is a relation between singularities and the type of tearing instabilities considered in the tokamak. Besides, in this case Ricci collineations and Killing symmetries are computed.The pressure is computed by applying these constraints to the pressure equations in tokamaks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('physics/0703014v1-abstract-full').style.display = 'none'; document.getElementById('physics/0703014v1-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 March, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2007. </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">Departamento de Fisica Teorica-IF-UERJ-Rio-Brasil</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/physics/0702203">arXiv:physics/0702203</a> <span> [<a href="https://arxiv.org/pdf/physics/0702203">pdf</a>, <a href="https://arxiv.org/ps/physics/0702203">ps</a>, <a href="https://arxiv.org/format/physics/0702203">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> <span class="tag is-small is-grey 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="Differential Geometry">math.DG</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Fluid Dynamics">physics.flu-dyn</span> </div> </div> <p class="title is-5 mathjax"> A Riemannian geometrical method to classify tearing instabilities in plasmas </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</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="physics/0702203v1-abstract-short" style="display: inline;"> Riemannian geometrical tools, such as Ricci collineations and Killing symmetries, so often used in Einstein general theory of gravitation are here applied to plasma physics to build magnetic surfaces from Einstein plasma metrics used in tokamak devices. It is shown that the Killing symmetries are constrains the Einstein magnetic surfaces while the Killing vectors are built in terms of the displa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('physics/0702203v1-abstract-full').style.display = 'inline'; document.getElementById('physics/0702203v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="physics/0702203v1-abstract-full" style="display: none;"> Riemannian geometrical tools, such as Ricci collineations and Killing symmetries, so often used in Einstein general theory of gravitation are here applied to plasma physics to build magnetic surfaces from Einstein plasma metrics used in tokamak devices. It is shown that the Killing symmetries are constrains the Einstein magnetic surfaces while the Killing vectors are built in terms of the displacement of the toroidal surface. The pressure is computed by applying these constraints to the pressure equations in tokamaks. A method, based on the sign of the only nontrivial constant Riemann curvature component, is suggested to classify tearing instability. Throughout the computations two approximations are considered: The first is the small toroidality and the other is the small displacement of the magnetic surfaces as Einstein spaces. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('physics/0702203v1-abstract-full').style.display = 'none'; document.getElementById('physics/0702203v1-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, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2007. </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">Depto de Fisica de Teorica-if-uerj-rio-Brasil</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/0702300">arXiv:astro-ph/0702300</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0702300">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0702300">ps</a>, <a href="https://arxiv.org/format/astro-ph/0702300">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> <span class="tag is-small is-grey 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="Plasma Physics">physics.plasm-ph</span> </div> </div> <p class="title is-5 mathjax"> Riemannian isometries of twisted magnetic flux tubes and stable current-carrying solar loops </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+G">Garcia de Andrade</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="astro-ph/0702300v1-abstract-short" style="display: inline;"> Two examples of the use of differential geometry in plasma physics are given: The first is the computation and solution of the constraint equations obtained from the Riemann metric isometry of the twisted flux tube. In this case a constraint between the Frenet torsion and curvature is obtained for inhomogeneous helical magnetic flux tube axis. In the second one, geometrical and topological const… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0702300v1-abstract-full').style.display = 'inline'; document.getElementById('astro-ph/0702300v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0702300v1-abstract-full" style="display: none;"> Two examples of the use of differential geometry in plasma physics are given: The first is the computation and solution of the constraint equations obtained from the Riemann metric isometry of the twisted flux tube. In this case a constraint between the Frenet torsion and curvature is obtained for inhomogeneous helical magnetic flux tube axis. In the second one, geometrical and topological constraints on the current-carrying solar loops are obtained by assuming that the plasma filament is stable. This is analogous to early computations by Liley [(Plasma Physics (1964)] in the case of hydromagnetic equilibria of magnetic surfaces. It is shown that exists a relationship between the ratio of the current components along and cross the plasma filament and the Frenet torsion and curvature. The computations are performed for the helical plasma filaments where torsion and curvature are proportional. The constraints imposed on the electric currents by the energy stability condition are used to solve the remaining magnetohydrodynamical (MHD) equations which in turn allows us to compute magnetic helicity and from them the twist and writhe topological numbers. Magnetic energy is also computed from the solutions of MHD equations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0702300v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0702300v1-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 February, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2007. </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">Departamento de Fisica Teorica-IF-UERJ-Rio-Brasil. submitted to physics of plasmas</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0509034">arXiv:gr-qc/0509034</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0509034">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0509034">ps</a>, <a href="https://arxiv.org/format/gr-qc/0509034">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> </div> </div> <p class="title is-5 mathjax"> Analogue non-Riemannian black holes in vortical moving plasmas </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0509034v1-abstract-short" style="display: inline;"> Analogue black holes in non-Riemannian effective spacetime of moving vortical plasmas described by moving magnetohydrodynamic (MHD) flows. This example is an extension of acoustic torsion recently introduced in the literature (Garcia de Andrade,PRD(2004),7,64004), where now the presence of artificial black holes in moving plasmas is obtained by the presence of an horizon in the non-Riemannian sp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0509034v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0509034v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0509034v1-abstract-full" style="display: none;"> Analogue black holes in non-Riemannian effective spacetime of moving vortical plasmas described by moving magnetohydrodynamic (MHD) flows. This example is an extension of acoustic torsion recently introduced in the literature (Garcia de Andrade,PRD(2004),7,64004), where now the presence of artificial black holes in moving plasmas is obtained by the presence of an horizon in the non-Riemannian spacetime. Hawking radiation is computed in terms of the background magnetic field and the magnetic permeability. The metric is singular although Cartan analogue torsion is not necessarily singular. The effective Lorentz invariance is shown to be broken due to the presence of effective torsion in strong analogy with the Riemann-Cartan gravitational case presented recently by Kostelecky (PRD 69,2004,105009). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0509034v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0509034v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 September, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2005. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0509027">arXiv:gr-qc/0509027</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0509027">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0509027">ps</a>, <a href="https://arxiv.org/format/gr-qc/0509027">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> </div> </div> <p class="title is-5 mathjax"> Hawking radiation in moving plasmas </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0509027v1-abstract-short" style="display: inline;"> Bi-metricity and Hawking radiation are exhibit in non-relativistic moving magnetohydrodynamics (MHD) plasma medium generating two Riemannian effective spacetimes. The first metric is a flat metric although the speed of "light" is given by a time dependent signal where no Hawking radiation or effective black holes are displayed. This metric comes from a wave equation which the scalar function com… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0509027v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0509027v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0509027v1-abstract-full" style="display: none;"> Bi-metricity and Hawking radiation are exhibit in non-relativistic moving magnetohydrodynamics (MHD) plasma medium generating two Riemannian effective spacetimes. The first metric is a flat metric although the speed of "light" is given by a time dependent signal where no Hawking radiation or effective black holes are displayed. This metric comes from a wave equation which the scalar function comes from the scalar potential of the background velocity of the fluid and depends on the perturbation of the magnetic background field. The second metric is an effective spacetime metric which comes from the perturbation of the background MHD fluid. This Riemann metric exhibits a horizon and Hawking radiation which can be expressed in terms of the background constant magnetic field. The effective velocity is given Alfven wave velocity of plasma physics. The effective black hole found here is analogous to the optical black hole in moving dielectrics found by De Lorenci et al [Phys. Rev. D (2003)] where bi-metricity and Hawking radiation in terms of the electric field are found. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0509027v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0509027v1-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 September, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2005. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0503088">arXiv:gr-qc/0503088</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0503088">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0503088">ps</a>, <a href="https://arxiv.org/format/gr-qc/0503088">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> </div> </div> <p class="title is-5 mathjax"> Relativistic superfluid hydrodynamics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0503088v1-abstract-short" style="display: inline;"> Relativistic Riemannian superfluid hydrodynamics used in general relativity to investigate superfluids in pulsars is extended to non-Riemannian background spacetime endowed with Cartan torsion. From the Gross-Pitaeviskii (GP) it is shown that in the weak field Cartan torsion approximation, the torsion vector is orthogonal to the superfluid plane wave velocity. Torsion vector is also shown to be… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0503088v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0503088v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0503088v1-abstract-full" style="display: none;"> Relativistic Riemannian superfluid hydrodynamics used in general relativity to investigate superfluids in pulsars is extended to non-Riemannian background spacetime endowed with Cartan torsion. From the Gross-Pitaeviskii (GP) it is shown that in the weak field Cartan torsion approximation, the torsion vector is orthogonal to the superfluid plane wave velocity. Torsion vector is also shown to be aligned along the vortex direction in the superfluid. The background torsion is shown to induce rotation on the fluid as happens with the acoustic torsion in the analogue non-Riemannian non-relativistic superfluid models. The torsion part of the current would be connected to the normal part of the superfluid velocity while the Riemannian part of the velocity would be connected to the superfluid velocity itself. Magnus effect and the rotation of the superfluid are analysed. Since the Kalb-Ramond field is easily associated with torsion our method seems to be equivalent to the vortex-cosmic string relativistic superfluid method developed by Carter and Langlois to investigate rotating neutron stars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0503088v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0503088v1-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 March, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2005. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0502106">arXiv:gr-qc/0502106</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0502106">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0502106">ps</a>, <a href="https://arxiv.org/format/gr-qc/0502106">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> </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.2005.07.023">10.1016/j.physleta.2005.07.023 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The necessity of non-Riemannian acoustic spacetime in the fluids with vorticity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0502106v1-abstract-short" style="display: inline;"> The necessity of a newly proposed (PRD 70 (2004) 64004) non-Riemannian acoustic spacetime structure called acoustic torsion of sound wave equation in fluids with vorticity are discussed. It is shown that this structure, although not always necessary is present in fluids with vorticity even when the perturbation is rotational. This can be done by solving the Bergliaffa et al (Physica D (2004)) ga… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0502106v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0502106v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0502106v1-abstract-full" style="display: none;"> The necessity of a newly proposed (PRD 70 (2004) 64004) non-Riemannian acoustic spacetime structure called acoustic torsion of sound wave equation in fluids with vorticity are discussed. It is shown that this structure, although not always necessary is present in fluids with vorticity even when the perturbation is rotational. This can be done by solving the Bergliaffa et al (Physica D (2004)) gauge invariant equations for sound, superposed to a general background flow, needs to support a non-Riemannian acoustic geometry in effective spacetime. Bergliaffa et al have previously shown that a Riemannian structure cannot be associated to this gauge invariant general system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0502106v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0502106v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 February, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2005. </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">Latex file</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys.Lett. A346 (2005) 327-329 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0501050">arXiv:gr-qc/0501050</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0501050">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0501050">ps</a>, <a href="https://arxiv.org/format/gr-qc/0501050">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> </div> </div> <p class="title is-5 mathjax"> A teleparallel effective geometry for Einstein's unified field theory </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0501050v1-abstract-short" style="display: inline;"> Riemannian and teleparallel geometrical approaches to the investigation of Maxwell electrodynamics shown that a unified field theory of gravitation and electromagnetism a la Einstein can be obtained from a stationary metric. This idea contrasts with the recently proposed pre-metric electrodynamics by Hehl and Obukhov. In the teleparallel case the definition of the electric field is obtained stra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0501050v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0501050v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0501050v1-abstract-full" style="display: none;"> Riemannian and teleparallel geometrical approaches to the investigation of Maxwell electrodynamics shown that a unified field theory of gravitation and electromagnetism a la Einstein can be obtained from a stationary metric. This idea contrasts with the recently proposed pre-metric electrodynamics by Hehl and Obukhov. In the teleparallel case the definition of the electric field is obtained straightforward from the spacetime metric and the orthonormal basis frame of teleparallelism. In this case the only nonvanishing component of Cartan torsion is defined as the effective electric field. In this approach the gravitational potentials or metric coefficients are expressed in terms of the effective or analogous electric and magnetic potentials. Thefore the Maxwell equations in vacuum can be obtained by derivation of this electric field definition as usual. In the Riemannian case we consider an electrostatic spacetime where the Einstein equations in vacuum in the approximation of linear fields. The constraint of Einstein equations in vacuum are shown to lead or to the Coulomb equation or to a singular behaviour on the metric which would represent a kind of effective electrodynamic black hole event horizon. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0501050v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0501050v1-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 January, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2005. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0501028">arXiv:gr-qc/0501028</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0501028">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0501028">ps</a>, <a href="https://arxiv.org/format/gr-qc/0501028">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> </div> </div> <p class="title is-5 mathjax"> Non-Riemannian effective spacetime effects on Hawking radiation in superfluids </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0501028v1-abstract-short" style="display: inline;"> Riemannian effective spacetime description of Hawking radiation in $^{3}He-A$ superfluids is extended to non-Riemannian effective spacetime. An example is given of non-Riemannian effective geometry of the rotational motion of the superfluid vacuum around the vortex where the effective spacetime Cartan torsion can be associated to the Hawking giving rise to a physical interpretation of effective… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0501028v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0501028v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0501028v1-abstract-full" style="display: none;"> Riemannian effective spacetime description of Hawking radiation in $^{3}He-A$ superfluids is extended to non-Riemannian effective spacetime. An example is given of non-Riemannian effective geometry of the rotational motion of the superfluid vacuum around the vortex where the effective spacetime Cartan torsion can be associated to the Hawking giving rise to a physical interpretation of effective torsion recently introduced in the literature in the form of an acoustic torsion in superfluid $^{4}He$ (PRD-70(2004),064004). Curvature and torsion singularities of this $^{3}He-A$ fermionic superfluid are investigated. This Lense-Thirring effective metric, representing the superfluid vacuum in rotational motion, is shown not support Hawking radiation when the isotropic $^{4}He$ is restored at far distances from the vortex axis. Hawking radiation can be expressed also in topological solitons (moving domain walls) in fermionic superfluids in non-Riemannian (teleparallel) $(1+1)$ dimensional effective spacetime. A teleparallel solution is proposed where the quasiparticle speed is determined from the teleparallel geometry. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0501028v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0501028v1-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 January, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2005. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0411103">arXiv:gr-qc/0411103</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0411103">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0411103">ps</a>, <a href="https://arxiv.org/format/gr-qc/0411103">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> </div> </div> <p class="title is-5 mathjax"> Non-Riemannian acoustic black holes: Hawking radiation and Lorentz symmetry breaking </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0411103v2-abstract-short" style="display: inline;"> A non-Riemannian geometrical approach to the investigation of an acoustic black hole in irrotational mean flows, based on the Lighthill vortex sound theory is given. This additional example of analog gravity based on classical fluids is used to investigate the acoustic Lorentz violation. An example is given where the contortion vector is distributed along a ring inside the fluid which can be gra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0411103v2-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0411103v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0411103v2-abstract-full" style="display: none;"> A non-Riemannian geometrical approach to the investigation of an acoustic black hole in irrotational mean flows, based on the Lighthill vortex sound theory is given. This additional example of analog gravity based on classical fluids is used to investigate the acoustic Lorentz violation. An example is given where the contortion vector is distributed along a ring inside the fluid which can be gravitational analog of the torsion thick string spacetime defect. It is found that the linear background flow velocity approximation, acoustic Lorentz symmetry is breaking by the acoustic Cartan contortion in analogy to the spontaneous gravitational Lorentz breaking in Riemann-Cartan spacetime discovered recently by Kostelecky. We also show that although the acoustic torsion contributes to the fiducial observer acceleration, it is not present in Hawking radiation since is not presnt in the surface gravity of the acoustic black hole. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0411103v2-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0411103v2-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 November, 2004; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 November, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2004. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0411079">arXiv:gr-qc/0411079</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0411079">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0411079">ps</a>, <a href="https://arxiv.org/format/gr-qc/0411079">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> </div> </div> <p class="title is-5 mathjax"> Riemannian geometry of gravity waves turbulent black hole analogs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0411079v1-abstract-short" style="display: inline;"> The gravity water wave black (GWBH) hole analog discovered by Schutzhold and Unruh (SU) is extended to allow for the presence of turbulent shear flow. The Riemannian geometry of turbulent black holes (BH) analogs in water waves is computed in the case of laminar tirbulent shear flow. The Riemann curvature is constant and the geodesic deviation equation shows that the curvature acts locally as a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0411079v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0411079v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0411079v1-abstract-full" style="display: none;"> The gravity water wave black (GWBH) hole analog discovered by Schutzhold and Unruh (SU) is extended to allow for the presence of turbulent shear flow. The Riemannian geometry of turbulent black holes (BH) analogs in water waves is computed in the case of laminar tirbulent shear flow. The Riemann curvature is constant and the geodesic deviation equation shows that the curvature acts locally as a diverging lens and the stream lines on opposite sides of the analog black hole flow apart from each other. In this case it is shown that the curvature quantities can be expressed in terms of the Newtonian gravitational constant in the ergoregion. The dispersion relation is obtained for the case of constant flow injection. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0411079v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0411079v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 November, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2004. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0410036">arXiv:gr-qc/0410036</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0410036">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0410036">ps</a>, <a href="https://arxiv.org/format/gr-qc/0410036">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> </div> </div> <p class="title is-5 mathjax"> Non-Riemannian geometry of turbulent acoustic flows and analog gravity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0410036v1-abstract-short" style="display: inline;"> Non-Riemannian geometry of acoustic non-relativistic turbulent flows is irrotationally perturbed generating a acoustic geometry model with acoustic metric and acoustic Cartan contortion. The contortion term is due to nonlinearities in the turbulent fluid. The acoustic curvature and acoustic contortion are given by Dirac delta distributions. Violation of Lorentz invariance due to turbulence is co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0410036v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0410036v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0410036v1-abstract-full" style="display: none;"> Non-Riemannian geometry of acoustic non-relativistic turbulent flows is irrotationally perturbed generating a acoustic geometry model with acoustic metric and acoustic Cartan contortion. The contortion term is due to nonlinearities in the turbulent fluid. The acoustic curvature and acoustic contortion are given by Dirac delta distributions. Violation of Lorentz invariance due to turbulence is considered and analog gravity is suggested to be linked to planar acoustic domain walls. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0410036v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0410036v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 October, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2004. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0409116">arXiv:gr-qc/0409116</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0409116">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0409116">ps</a>, <a href="https://arxiv.org/format/gr-qc/0409116">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> </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.2005.02.076">10.1016/j.physleta.2005.02.076 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Non-Riemannian vortex geometry of rotational viscous fluids and breaking of the acoustic Lorentz invariance </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0409116v1-abstract-short" style="display: inline;"> Acoustic torsion recently introduced in the literature (Garcia de Andrade,PRD(2004),7,64004) is extended to rotational incompressible viscous fluids represented by the generalised Navier-Stokes equation. The fluid background is compared with the Riemann-Cartan massless scalar wave equation, allowing for the generalization of Unruh acoustic metric in the form of acoustic torsion, expressed in ter… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0409116v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0409116v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0409116v1-abstract-full" style="display: none;"> Acoustic torsion recently introduced in the literature (Garcia de Andrade,PRD(2004),7,64004) is extended to rotational incompressible viscous fluids represented by the generalised Navier-Stokes equation. The fluid background is compared with the Riemann-Cartan massless scalar wave equation, allowing for the generalization of Unruh acoustic metric in the form of acoustic torsion, expressed in terms of viscosity, velocity and vorticity of the fluid. In this work the background vorticity is nonvanishing but the perturbation of the flow is also rotational which avoids the problem of contamination of the irrotational perturbation by the background vorticity. The acoustic Lorentz invariance is shown to be broken due to the presence of acoustic torsion in strong analogy with the Riemann-Cartan gravitational case presented recently by Kostelecky (PRD 69,2004,105009). An example of analog gravity describing acoustic metric is given based on the teleparallel loop where the acoustic torsion is given by the Lense-Thirring rotation and the acoustic line element corresponds to the Lense-Thirring metric. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0409116v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0409116v1-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 September, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2004. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0409115">arXiv:gr-qc/0409115</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0409115">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0409115">ps</a>, <a href="https://arxiv.org/format/gr-qc/0409115">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> </div> </div> <p class="title is-5 mathjax"> Irrotational vortex geometry of torsion loops </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Anddrade%2C+L+C+G">L. C. Garcia de Anddrade</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="gr-qc/0409115v1-abstract-short" style="display: inline;"> The irrotational vortex geometry carachter of torsion loops is displayed by showing that torsion loops and nonradial flow acoustic metrics are conformally equivalent in $(1+1)$ dimensions while radial flow acoustic spacetime are conformally related in $(2+1)$ dimensional spacetime. The analysis of 2-dimensional space allows us to express the fluid density in terms of the parameters of torsion lo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0409115v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0409115v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0409115v1-abstract-full" style="display: none;"> The irrotational vortex geometry carachter of torsion loops is displayed by showing that torsion loops and nonradial flow acoustic metrics are conformally equivalent in $(1+1)$ dimensions while radial flow acoustic spacetime are conformally related in $(2+1)$ dimensional spacetime. The analysis of 2-dimensional space allows us to express the fluid density in terms of the parameters of torsion loop metric. These results lead us to conclude that the acoustic metric of vortex flows is the gravitational analog of torsion loop spacetime. Since no vorticity in the fluids is considered we do not make explicit use of non-Riemannian geometry of vortex acoustics in classical fluids. Acoustic nonradial flows are shown to exihibit a full analogy with torsion loop metric. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0409115v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0409115v1-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 September, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2004. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0406057">arXiv:gr-qc/0406057</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0406057">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0406057">ps</a>, <a href="https://arxiv.org/format/gr-qc/0406057">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> </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/10.1209/epl/i2004-10096-6">10.1209/epl/i2004-10096-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Geometric Phase for Fermionic Quasiparticles Scattering by Disgyration in Superfluids </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</a>, <a href="/search/gr-qc?searchtype=author&query=Carvalho%2C+A+M+d+M">A. M. de M. Carvalho</a>, <a href="/search/gr-qc?searchtype=author&query=Furtado%2C+C">C. Furtado</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="gr-qc/0406057v1-abstract-short" style="display: inline;"> We consider a Volovik's analog model for description of a topological defects in a superfluid and we investigate the scattering of quasiparticles in this background. The analog of the gravitational Aharonov-Bohm in this system is found. An analysis of this problem employing loop variables is considered and corroborates for the existence of the Aharonov-Bohm effect in this system. The results pre… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0406057v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0406057v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0406057v1-abstract-full" style="display: none;"> We consider a Volovik's analog model for description of a topological defects in a superfluid and we investigate the scattering of quasiparticles in this background. The analog of the gravitational Aharonov-Bohm in this system is found. An analysis of this problem employing loop variables is considered and corroborates for the existence of the Aharonov-Bohm effect in this system. The results presented here may be used to study the Aharonov-Bohm effect in superconductors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0406057v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0406057v1-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 June, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2004. </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, to appear in Europhys. Lett</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Europhys.Lett.67:538-544,2004 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0405062">arXiv:gr-qc/0405062</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0405062">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0405062">ps</a>, <a href="https://arxiv.org/format/gr-qc/0405062">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> </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/PhysRevD.70.064004">10.1103/PhysRevD.70.064004 <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/10.1103/PhysRevD.70.129903">10.1103/PhysRevD.70.129903 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Non-Riemannian geometry of vortex acoustics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0405062v2-abstract-short" style="display: inline;"> The concept of acoustic metric introduced previously by Unruh (PRL-1981) is extended to include Cartan torsion by analogy with the scalar wave equation in Riemann-Cartan (RC) spacetime. This equation describes irrotational perturbations in rotational non-relativistic fluids. This physical motivation allows us to show that the acoustic line element can be conformally mapped to the line element of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0405062v2-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0405062v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0405062v2-abstract-full" style="display: none;"> The concept of acoustic metric introduced previously by Unruh (PRL-1981) is extended to include Cartan torsion by analogy with the scalar wave equation in Riemann-Cartan (RC) spacetime. This equation describes irrotational perturbations in rotational non-relativistic fluids. This physical motivation allows us to show that the acoustic line element can be conformally mapped to the line element of a stationary torsion loop in non-Riemannian gravity. Two examples of such sonic analogues are given. The first is when we choose the static torsion loop in teleparallel gravity. In this case Cartan torsion vector in the far from the vortex approximation is shown to be proportional to the quantum vortex number of the superfluid. Also in this case the torsion vector is shown to be proportional to the superfluid vorticity in the presence of vortices. Torsion loops in RC spacetime does not favor the formation of superfluid vortices. It is suggested that the teleparallel model may help to find a model for superfluid neutron stars vortices based on non-Riemannian gravity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0405062v2-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0405062v2-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 May, 2004; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 May, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2004. </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">Some additions to the last section: Demonstration that torsion vector is proportional to the number of vortices in the superfluid and some formulas omitted</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys.Rev.D70:064004,2004; Erratum-ibid.D70:129903,2004 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0401025">arXiv:gr-qc/0401025</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0401025">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0401025">ps</a>, <a href="https://arxiv.org/format/gr-qc/0401025">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> </div> </div> <p class="title is-5 mathjax"> Holonomy, Aharonov-Bohm effect and phonon scattering in superfluids </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Furtado%2C+C">Claudio Furtado</a>, <a href="/search/gr-qc?searchtype=author&query=Carvalho%2C+A+M+d+M">A. M. de M. Carvalho</a>, <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</a>, <a href="/search/gr-qc?searchtype=author&query=Moraes%2C+F">F. Moraes</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="gr-qc/0401025v1-abstract-short" style="display: inline;"> In this article we discuss the analogy between superfluids and a spinning thick cosmic string. We use the geometrical approach to obtain the geometrical phases for a phonon in the presence of a vortex. We use loop variables for a geometric description of Aharonov-Bohm effect in these systems. We use holonomy transformations to characterize globally the "space-time" of a vortex and in this point… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0401025v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0401025v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0401025v1-abstract-full" style="display: none;"> In this article we discuss the analogy between superfluids and a spinning thick cosmic string. We use the geometrical approach to obtain the geometrical phases for a phonon in the presence of a vortex. We use loop variables for a geometric description of Aharonov-Bohm effect in these systems. We use holonomy transformations to characterize globally the "space-time" of a vortex and in this point of view we study the gravitational analog of the Aharonov-Bohm effect in this system. We demonstrate that in the general case the Aharonov-Bohm effect has a contribution both from the rotational and the translational holonomy. We study also Berrys quantum phase for phonons in this systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0401025v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0401025v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 January, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2004. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, Revtex4</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0302042">arXiv:gr-qc/0302042</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0302042">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0302042">ps</a>, <a href="https://arxiv.org/format/gr-qc/0302042">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> </div> </div> <p class="title is-5 mathjax"> Analytical solution of the neutrino wave equation in Kerr geometry with Vaidya-Patel coordinates </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0302042v1-abstract-short" style="display: inline;"> Analytical solution of Weyl neutrino wave equation in Kerr geometry is presented by making use of the two-spinor component spin-coefficient Newman-Penrose (NP) calculus. So far only asymptotic or approximate solutions have been found for the Weyl equation in this background. It is shown that neutrino current asymmetry is also present in this solution. </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0302042v1-abstract-full" style="display: none;"> Analytical solution of Weyl neutrino wave equation in Kerr geometry is presented by making use of the two-spinor component spin-coefficient Newman-Penrose (NP) calculus. So far only asymptotic or approximate solutions have been found for the Weyl equation in this background. It is shown that neutrino current asymmetry is also present in this solution. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0302042v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0302042v1-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 February, 2003; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2003. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0301074">arXiv:gr-qc/0301074</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0301074">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0301074">ps</a>, <a href="https://arxiv.org/format/gr-qc/0301074">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> </div> </div> <p class="title is-5 mathjax"> Non-Riemannian geometrical optics in QED </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0301074v1-abstract-short" style="display: inline;"> A non-minimal photon-torsion axial coupling in the quantum electrodynamics (QED) framework is considered. The geometrical optics in Riemannian-Cartan spacetime is considering and a plane wave expansion of the electromagnetic vector potential is considered leading to a set of the equations for the ray congruence. Since we are interested mainly on the torsion effects in this first report we just c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0301074v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0301074v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0301074v1-abstract-full" style="display: none;"> A non-minimal photon-torsion axial coupling in the quantum electrodynamics (QED) framework is considered. The geometrical optics in Riemannian-Cartan spacetime is considering and a plane wave expansion of the electromagnetic vector potential is considered leading to a set of the equations for the ray congruence. Since we are interested mainly on the torsion effects in this first report we just consider the Riemann-flat case composed of the Minkowskian spacetime with torsion. It is also shown that in torsionic de Sitter background the vacuum polarisation does alter the propagation of individual photons, an effect which is absent in Riemannian spaces. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0301074v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0301074v1-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 January, 2003; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2003. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0301013">arXiv:gr-qc/0301013</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0301013">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0301013">ps</a>, <a href="https://arxiv.org/format/gr-qc/0301013">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> </div> </div> <p class="title is-5 mathjax"> On non-Riemannian geometry of superfluids </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0301013v1-abstract-short" style="display: inline;"> The Gross-Pitaevski (GP) equation describing helium superfluids is extended to non-Riemannian spacetime background where torsion is shown to induce the splitting in the potential energy of the flow. A cylindrically symmetric solution for Minkowski background with constant torsion is obtained which shows that torsion induces a damping on the superfluid flow velocity. The Sagnac phase shift is com… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0301013v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0301013v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0301013v1-abstract-full" style="display: none;"> The Gross-Pitaevski (GP) equation describing helium superfluids is extended to non-Riemannian spacetime background where torsion is shown to induce the splitting in the potential energy of the flow. A cylindrically symmetric solution for Minkowski background with constant torsion is obtained which shows that torsion induces a damping on the superfluid flow velocity. The Sagnac phase shift is computed from the superfluid flow velocity obtained from the solution of GP equations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0301013v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0301013v1-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> 5 January, 2003; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2003. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0211072">arXiv:gr-qc/0211072</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0211072">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0211072">ps</a>, <a href="https://arxiv.org/format/gr-qc/0211072">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> </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/10.1023/A:1024406009917">10.1023/A:1024406009917 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Spin polarised magnetized cylinder in torsioned spacetime </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0211072v1-abstract-short" style="display: inline;"> A Spin-polarised cylindrically symmetric exact class of solutions endowed with magnetic fields in Einstein-Cartan-Maxwell gravity is obtained. Application of matching conditions to this interior solution having an exterior as Einstein's vacuum solution shows that for this class of metrics the Riemann-Cartan (RC) rotation vanishes which makes the solution static. Therefore we end up with a magnet… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0211072v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0211072v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0211072v1-abstract-full" style="display: none;"> A Spin-polarised cylindrically symmetric exact class of solutions endowed with magnetic fields in Einstein-Cartan-Maxwell gravity is obtained. Application of matching conditions to this interior solution having an exterior as Einstein's vacuum solution shows that for this class of metrics the Riemann-Cartan (RC) rotation vanishes which makes the solution static. Therefore we end up with a magnetized static spin polarised cylinder where the pressure along the symmetry axis is negative. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0211072v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0211072v1-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 November, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2002. </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">Latex file</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Gen.Rel.Grav. 35 (2003) 1279-1283 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0210107">arXiv:gr-qc/0210107</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0210107">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0210107">ps</a>, <a href="https://arxiv.org/format/gr-qc/0210107">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> </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/S0218271803003323">10.1142/S0218271803003323 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Neutrino asymmetry in general relativistic rotating radiative stars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0210107v1-abstract-short" style="display: inline;"> Neutrino asymmetry in general relativistic radiative spacetime exterior to spinning stars is investigating by making use of Newmann-Penrose (NP) spin coefficient formalism. It is shown that neutrino current depends on the direction of rotation of the star. The solution is obtained in test field approximation where the neutrinos do not generate gravitational fields. </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0210107v1-abstract-full" style="display: none;"> Neutrino asymmetry in general relativistic radiative spacetime exterior to spinning stars is investigating by making use of Newmann-Penrose (NP) spin coefficient formalism. It is shown that neutrino current depends on the direction of rotation of the star. The solution is obtained in test field approximation where the neutrinos do not generate gravitational fields. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0210107v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0210107v1-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, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2002. </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">Latex file</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Int.J.Mod.Phys.D12:1047-1052,2003 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0208071">arXiv:gr-qc/0208071</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0208071">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0208071">ps</a>, <a href="https://arxiv.org/format/gr-qc/0208071">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> </div> </div> <p class="title is-5 mathjax"> Spin polarised particles in Goedel world </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0208071v1-abstract-short" style="display: inline;"> The motion of classical test spinning particles in Godel universe in the realm of Einstein's General Relativity (GR) is investigated by making use of Killing conserved currents. We consider three distinct cases of motion of spinning particles polarized along the three distinct axes of the anisotropic metric. It is shown that in the case the spin is polarised along the y-direction the minimum ene… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0208071v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0208071v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0208071v1-abstract-full" style="display: none;"> The motion of classical test spinning particles in Godel universe in the realm of Einstein's General Relativity (GR) is investigated by making use of Killing conserved currents. We consider three distinct cases of motion of spinning particles polarized along the three distinct axes of the anisotropic metric. It is shown that in the case the spin is polarised along the y-direction the minimum energy of the motion is attained for only for spinless particles while the other two directions the minimum energy is obtained for spinning particles. The continuos energy spectrum is also computed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0208071v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0208071v1-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 August, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2002. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0207034">arXiv:gr-qc/0207034</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0207034">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0207034">ps</a>, <a href="https://arxiv.org/format/gr-qc/0207034">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> </div> </div> <p class="title is-5 mathjax"> Energy spectra of spinning particles around spinning strings in Einstein-Cartan gravity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0207034v2-abstract-short" style="display: inline;"> Riemannian Killing conserved currents are used to find the energy spectra of classical spinning particles moving around a spinning string in Einstein-Cartan (EC) theory of gravity. It is shown that a continuos spectrum is obtained for planar open orbits the energy shift between the upper and lower bounds obtained for circular planar orbits. A spin-spin effect between the spin of the test particl… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0207034v2-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0207034v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0207034v2-abstract-full" style="display: none;"> Riemannian Killing conserved currents are used to find the energy spectra of classical spinning particles moving around a spinning string in Einstein-Cartan (EC) theory of gravity. It is shown that a continuos spectrum is obtained for planar open orbits the energy shift between the upper and lower bounds obtained for circular planar orbits. A spin-spin effect between the spin of the test particle and the spin of the spinning string contributes to the energy spectrum splitting. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0207034v2-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0207034v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 July, 2002; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 July, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2002. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0206007">arXiv:gr-qc/0206007</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0206007">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0206007">ps</a>, <a href="https://arxiv.org/format/gr-qc/0206007">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> </div> </div> <p class="title is-5 mathjax"> Gravitational and torsion waves in linearised teleparallel gravity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0206007v1-abstract-short" style="display: inline;"> Spin-2, spin-1 and spin-0 modes in linearised teleparallelism are obtained where the totally skew-symmetric complex contortion tensor generates scalar torsion waves and the symmetric contortion in the last two indices generates gravitational waves as gravitational perturbations of flat spacetime with contortion tensor. A gedanken experiment with this gravitational-torsion wave hitting a ring of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0206007v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0206007v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0206007v1-abstract-full" style="display: none;"> Spin-2, spin-1 and spin-0 modes in linearised teleparallelism are obtained where the totally skew-symmetric complex contortion tensor generates scalar torsion waves and the symmetric contortion in the last two indices generates gravitational waves as gravitational perturbations of flat spacetime with contortion tensor. A gedanken experiment with this gravitational-torsion wave hitting a ring of spinless particles is proposed which allows us to estimate the contortion of the Earth by making use of data from LISA GW detector. This value coincides with previous value obtained by Nitsch in teleparallelism using another type of experiment. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0206007v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0206007v1-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 June, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2002. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0205120">arXiv:gr-qc/0205120</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0205120">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0205120">ps</a>, <a href="https://arxiv.org/format/gr-qc/0205120">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> </div> </div> <p class="title is-5 mathjax"> Nongeodesic motion of spinless particles in the teleparallel gravitational wave background </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0205120v1-abstract-short" style="display: inline;"> The motion of spinless particles in Riemann-Cartan (RC) $U_{4}$ and teleparallel spacetimes is revisited on the light of gravitational waves hitting on the spinless test particles. It is shown that in the case Cartan contortion is totally skew-symmetric the spinless particles follow geodesics but if this symmetry is dropped they are able to follow nongeodesic worldlines in torsionic background.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0205120v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0205120v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0205120v1-abstract-full" style="display: none;"> The motion of spinless particles in Riemann-Cartan (RC) $U_{4}$ and teleparallel spacetimes is revisited on the light of gravitational waves hitting on the spinless test particles. It is shown that in the case Cartan contortion is totally skew-symmetric the spinless particles follow geodesics but if this symmetry is dropped they are able to follow nongeodesic worldlines in torsionic background. The case of totally skew contortion and spinning particles may appear either in $T_{4}$ or $U_{4}$ spacetimes. We consider $T_{4}$ nongeodesic motion of spinless test particles in the field of gravitational waves (GW). It is shown that the general contortion obeys a tensor wave constraint and the analysis of a ring of spinless test particles as in General Relativity (GR) hit by the GW leads to damping contortion effects on the nongeodesic motion is undertaken. It is also shown that the contortion and gravitational waves possess a difference of phase of $\frac蟺{2}$ and a contortion at the surface of the Earth of $10^{-24} s^{-1}$ computed by Nitsch in the realm of teleparallelism is used to obtain a deviation of the lenght of the separation of test spinless particles compatible with the GR result. To obtain this result data from GW LISA detector is used. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0205120v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0205120v1-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, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2002. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0204084">arXiv:gr-qc/0204084</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0204084">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0204084">ps</a>, <a href="https://arxiv.org/format/gr-qc/0204084">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> </div> </div> <p class="title is-5 mathjax"> Ghost neutrinos and radiative Kerr metric in Einstein-Cartan gravity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0204084v1-abstract-short" style="display: inline;"> Ghost neutrinos in radiative Kerr spacetime endowed with totally skew-symmetric Cartan contortion is presented. The computations are made by using the Newman-Penrose (NP) calculus. The model discussed here maybe useful in several astrophysical applications specially in black hole astrophysics. </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0204084v1-abstract-full" style="display: none;"> Ghost neutrinos in radiative Kerr spacetime endowed with totally skew-symmetric Cartan contortion is presented. The computations are made by using the Newman-Penrose (NP) calculus. The model discussed here maybe useful in several astrophysical applications specially in black hole astrophysics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0204084v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0204084v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 April, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2002. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0203089">arXiv:gr-qc/0203089</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0203089">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0203089">ps</a>, <a href="https://arxiv.org/format/gr-qc/0203089">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> </div> </div> <p class="title is-5 mathjax"> A comment on the inhomogeneous Einstein-Cartan-Kalb-Ramond fields in Cosmology </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0203089v1-abstract-short" style="display: inline;"> Purely time dependent solutions in four-dimensional Einstein-Cartan-Kalb-Ramond (ECKR) theory of gravity are shown not to be possible leading to a trivial vanishing of all Kalb-Ramond fields. This result seems to contradict previously results obtained by SenGupta et al. (Class. and Quantum Gravity 19(2002)677) where de Sitter spacetime solution is found as an example of opticaly active spacetime… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0203089v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0203089v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0203089v1-abstract-full" style="display: none;"> Purely time dependent solutions in four-dimensional Einstein-Cartan-Kalb-Ramond (ECKR) theory of gravity are shown not to be possible leading to a trivial vanishing of all Kalb-Ramond fields. This result seems to contradict previously results obtained by SenGupta et al. (Class. and Quantum Gravity 19(2002)677) where de Sitter spacetime solution is found as an example of opticaly active spacetime. It seems that only inhomogeneous KR fields are possible in four-dimensional torsioned spacetimes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0203089v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0203089v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 March, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2002. </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">Latex file</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0202022">arXiv:gr-qc/0202022</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0202022">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0202022">ps</a>, <a href="https://arxiv.org/format/gr-qc/0202022">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> </div> </div> <p class="title is-5 mathjax"> Metric perturbations in Einstein-Cartan Cosmology </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=de+Andrade%2C+L+C+G">L. C. Garcia de Andrade</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="gr-qc/0202022v1-abstract-short" style="display: inline;"> Metric perturbations the stability of solution of Einstein-Cartan cosmology (ECC) are given. The first addresses the stability of solutions of Einstein-Cartan (EC) cosmological model against Einstein static universe background. In this solution we show that the metric is stable against first-order perturbations and correspond to acoustic oscillations. The second example deals with the stability… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0202022v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0202022v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0202022v1-abstract-full" style="display: none;"> Metric perturbations the stability of solution of Einstein-Cartan cosmology (ECC) are given. The first addresses the stability of solutions of Einstein-Cartan (EC) cosmological model against Einstein static universe background. In this solution we show that the metric is stable against first-order perturbations and correspond to acoustic oscillations. The second example deals with the stability of de Sitter metric also against first-order perturbations. Torsion and shear are also computed in these cases. The resultant perturbed anisotropic spacetime with torsion is only de Sitter along one direction or is unperturbed along one direction and perturbed against the other two. Cartan torsion contributes to the frequency of oscillations in the model. Therefore gravitational waves could be triggered by the spin-torsion scalar density . <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0202022v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0202022v1-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 February, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2002. </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">Latex file</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=de+Andrade%2C+L&start=50" 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