The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Jiro Soda - One of the best experts on this subject based on the ideXlab platform.
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Stability of squashed Kaluza-Klein black holes
Physical Review D, 2008Co-Authors: Masashi Kimura, Keiju Murata, Hideki Ishihara, Jiro SodaAbstract:The stability of squashed Kaluza-Klein black holes is studied. The squashed Kaluza-Klein black hole looks like a five-dimensional black hole in the vicinity of horizon and looks like a four-dimensional Minkowski spacetime with a circle at infinity. In this sense, squashed Kaluza-Klein black holes can be regarded as black holes in the Kaluza-Klein spacetimes. Using the symmetry of squashed Kaluza-Klein black holes, $SU(2)\ifmmode\times\else\texttimes\fi{}U(1)\ensuremath{\simeq}U(2)$, we obtain master equations for a part of the metric perturbations relevant to the stability. The analysis based on the master equations gives strong evidence for the stability of squashed Kaluza-Klein black holes. Hence, the squashed Kaluza-Klein black holes deserve to be taken seriously as realistic black holes in the Kaluza-Klein spacetime.
Masashi Kimura - One of the best experts on this subject based on the ideXlab platform.
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Stability of squashed Kaluza-Klein black holes
Physical Review D, 2008Co-Authors: Masashi Kimura, Keiju Murata, Hideki Ishihara, Jiro SodaAbstract:The stability of squashed Kaluza-Klein black holes is studied. The squashed Kaluza-Klein black hole looks like a five-dimensional black hole in the vicinity of horizon and looks like a four-dimensional Minkowski spacetime with a circle at infinity. In this sense, squashed Kaluza-Klein black holes can be regarded as black holes in the Kaluza-Klein spacetimes. Using the symmetry of squashed Kaluza-Klein black holes, $SU(2)\ifmmode\times\else\texttimes\fi{}U(1)\ensuremath{\simeq}U(2)$, we obtain master equations for a part of the metric perturbations relevant to the stability. The analysis based on the master equations gives strong evidence for the stability of squashed Kaluza-Klein black holes. Hence, the squashed Kaluza-Klein black holes deserve to be taken seriously as realistic black holes in the Kaluza-Klein spacetime.
Tower Wang - One of the best experts on this subject based on the ideXlab platform.
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a rotating kaluza klein black hole with squashed horizons
Nuclear Physics, 2006Co-Authors: Tower WangAbstract:We find a rotating Kaluza-Klein black hole solution with squashed S-3 horizons in five dimensions. This is a Kerr counterpart of the charged one found by Ishihara and Matsuno [H. Ishihara, K. Matsuno, Kaluza-Klein black holes with squashed horizons. hep-th/0510094] recently. The space-time is geodesic complete and free of naked singularities. Its asymptotic structure is a twisted S' fiber bundle over a four-dimensional Minkowski space-time. We also study the mass and thermodynamics of this black hole. (c) 2006 Elsevier B.V. All rights reserved.
Andreas Winter - One of the best experts on this subject based on the ideXlab platform.
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Relative Entropy and Squashed Entanglement
Communications in Mathematical Physics, 2014Co-Authors: Andreas WinterAbstract:We are interested in the properties and relations of entanglement measures. Especially, we focus on the squashed entanglement and relative entropy of entanglement, as well as their analogues and variants. Our first result is a monogamy-like inequality involving the relative entropy of entanglement and its one-way LOCC variant. The proof is accomplished by exploring the properties of relative entropy in the context of hypothesis testing via one-way LOCC operations, and by making use of an argument resembling that by Piani on the faithfulness of regularized relative entropy of entanglement. Following this, we obtain a commensurate and faithful lower bound for squashed entanglement, in the form of one-way LOCC relative entropy of entanglement. This gives a strengthening to the strong subadditivity of von Neumann entropy. Our result improves the trace-distance-type bound derived in Brandão et al. (Commun Math Phys, 306:805–830, 2011 ), where faithfulness of squashed entanglement was first proved. Applying Pinsker’s inequality, we are able to recover the trace-distance-type bound, even with slightly better constant factor. However, the main improvement is that our new lower bound can be much larger than the old one and it is almost a genuine entanglement measure. We evaluate exactly the relative entropy of entanglement under various restricted measurement classes, for maximally entangled states. Then, by proving asymptotic continuity, we extend the exact evaluation to their regularized versions for all pure states. Finally, we consider comparisons and separations between some important entanglement measures and obtain several new results on these, too.
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relative entropy and squashed entanglement
Communications in Mathematical Physics, 2014Co-Authors: Ke Li, Andreas WinterAbstract:We are interested in the properties and relations of entanglement measures. Especially, we focus on the squashed entanglement and relative entropy of entanglement, as well as their analogues and variants.
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“Squashed entanglement”: An additive entanglement measure
Journal of Mathematical Physics, 2004Co-Authors: Matthias Christandl, Andreas WinterAbstract:In this paper, we present a new entanglement monotone for bipartite quantum states. Its definition is inspired by the so-called intrinsic information of classical cryptography and is given by the halved minimum quantum conditional mutual information over all tripartite state extensions. We derive certain properties of the new measure which we call “squashed entanglement”: it is a lower bound on entanglement of formation and an upper bound on distillable entanglement. Furthermore, it is convex, additive on tensor products, and superadditive in general. Continuity in the state is the only property of our entanglement measure which we cannot provide a proof for. We present some evidence, however, that our quantity has this property, the strongest indication being a conjectured Fannes-type inequality for the conditional von Neumann entropy. This inequality is proved in the classical case.
Kentaroh Yoshida - One of the best experts on this subject based on the ideXlab platform.
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hybrid classical integrability in squashed sigma models
Physics Letters B, 2011Co-Authors: Io Kawaguchi, Kentaroh YoshidaAbstract:Abstract We show that SU ( 2 ) L Yangian and q-deformed SU ( 2 ) R symmetries are realized in a two-dimensional sigma model defined on a three-dimensional squashed sphere. These symmetries enable us to develop the two descriptions to describe its classical dynamics, 1) rational and 2) trigonometric descriptions. The former 1) is based on the SU ( 2 ) L symmetry and the latter 2) comes from the broken SU ( 2 ) R symmetry. Each of the Lax pairs constructed in both ways leads to the same equations of motion. The two descriptions are related to one another through a non-local map.
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hidden yangian symmetry in sigma model on squashed sphere
Journal of High Energy Physics, 2010Co-Authors: Io Kawaguchi, Kentaroh YoshidaAbstract:We discuss a hidden symmetry of a two-dimensional sigma model on a squashed S 3. The SU(2) current can be improved so that it can be regarded as a flat connection. Then we can obtain an infinite number of conserved non-local charges and show the Yangian algebra by directly checking the Serre relations. This symmetry is also deduced from the coset structure of the squashed sphere. The same argument is applicable to the warped AdS3 spaces by the double Wick rotations.
