We calculate the contributions of a general non-vacuum conformal family to R′enyi entropy in twodimensional conformal field theory（CFT）. The primary operator of the conformal family can be either non-chiral or chir...We calculate the contributions of a general non-vacuum conformal family to R′enyi entropy in twodimensional conformal field theory（CFT）. The primary operator of the conformal family can be either non-chiral or chiral, and we denote its scaling dimension by ？. For the case of two short intervals on a complex plane, we expand the R′enyi mutual information by the cross ratio x to order x^（2△＋2）. For the case of one interval on a torus with low temperature, we expand the R′enyi entropy by q = exp（-2πβ/L）, with β being the inverse temperature and L being the spatial period, to order q^（△＋2）. To make the result meaningful, we require that the scaling dimension ？ cannot be too small. For two intervals on a complex plane we need △ 〉 1, and for one interval on a torus we need △ 〉 2.We work in the small Newton constant limit on the gravity side and so a large central charge limit on the CFT side,and find matches of gravity and CFT results.展开更多
We investigate the exact results for circular 1/4 and 1/2 BPS Wilson loops in the d = 3 N = 4 super Chern-Simons-matter theory that could be obtained by orbifolding Aharony-Bergman-Jafferis-Maldacena （ABJM） theory. ...We investigate the exact results for circular 1/4 and 1/2 BPS Wilson loops in the d = 3 N = 4 super Chern-Simons-matter theory that could be obtained by orbifolding Aharony-Bergman-Jafferis-Maldacena （ABJM） theory. The partition function of the Af = 4 orbifold ABJM theory has been computed previously in the literature. In this paper, we re-derive it using a slightly different method. We calculate the vacuum expectation values of the circular 1/4 BPS Wilson loops in fundamental representation and of circular 1/2 BPS Wilson loops in arbitrary representations. We use both the saddle point approach and Fermi gas approach. The results for Wilson loops are in accord with the available gravity results.展开更多
We study the asymptotic symmetry group (ASG) of the near horizon geometry of extreme Kerr black hole through the effective action approach developed by Porfyriadis and Wilczek (arXiv:1007.1031v1[gr qc]).By requiring a...We study the asymptotic symmetry group (ASG) of the near horizon geometry of extreme Kerr black hole through the effective action approach developed by Porfyriadis and Wilczek (arXiv:1007.1031v1[gr qc]).By requiring a finite boundary effective action,we derive a new set of asymptotic Killing vectors and boundary conditions,which are much more relaxed than the ones proposed by Matsuo Y et al.[Nucl.Phys.B 825 (2010) 231],and still allow a copy of a conformal group as its ASG.In the covariant formalism,the asymptotic charges are finite,with the corresponding central charge vanishing.By using the quasi-local charge and introducing a plausible cut-off,we find that the higher order terms of the asymptotic Killing vectors,which could not be determined through the effective action approach,contribute to the central charge as well.We also show that the boundary conditions suggested by Guica et al.[Phys.Rev.D 80 (2009)124008] lead to a divergent first-order boundary effective action.展开更多
基金Supported by ERC Starting Grant 637844-HBQFTNCER
文摘We calculate the contributions of a general non-vacuum conformal family to R′enyi entropy in twodimensional conformal field theory（CFT）. The primary operator of the conformal family can be either non-chiral or chiral, and we denote its scaling dimension by ？. For the case of two short intervals on a complex plane, we expand the R′enyi mutual information by the cross ratio x to order x^（2△＋2）. For the case of one interval on a torus with low temperature, we expand the R′enyi entropy by q = exp（-2πβ/L）, with β being the inverse temperature and L being the spatial period, to order q^（△＋2）. To make the result meaningful, we require that the scaling dimension ？ cannot be too small. For two intervals on a complex plane we need △ 〉 1, and for one interval on a torus we need △ 〉 2.We work in the small Newton constant limit on the gravity side and so a large central charge limit on the CFT side,and find matches of gravity and CFT results.
基金Supported by NSFC(11222549,11575202)K.C.Wong Education FoundationYouth Innovation Promotion Association of CAS(2011016)
文摘We investigate the exact results for circular 1/4 and 1/2 BPS Wilson loops in the d = 3 N = 4 super Chern-Simons-matter theory that could be obtained by orbifolding Aharony-Bergman-Jafferis-Maldacena （ABJM） theory. The partition function of the Af = 4 orbifold ABJM theory has been computed previously in the literature. In this paper, we re-derive it using a slightly different method. We calculate the vacuum expectation values of the circular 1/4 BPS Wilson loops in fundamental representation and of circular 1/2 BPS Wilson loops in arbitrary representations. We use both the saddle point approach and Fermi gas approach. The results for Wilson loops are in accord with the available gravity results.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10775002 and 10975005the Special Fund for Theoretical Physics from the National Natural Science Foundations of China under Grant No 10947203.
文摘We study the asymptotic symmetry group (ASG) of the near horizon geometry of extreme Kerr black hole through the effective action approach developed by Porfyriadis and Wilczek (arXiv:1007.1031v1[gr qc]).By requiring a finite boundary effective action,we derive a new set of asymptotic Killing vectors and boundary conditions,which are much more relaxed than the ones proposed by Matsuo Y et al.[Nucl.Phys.B 825 (2010) 231],and still allow a copy of a conformal group as its ASG.In the covariant formalism,the asymptotic charges are finite,with the corresponding central charge vanishing.By using the quasi-local charge and introducing a plausible cut-off,we find that the higher order terms of the asymptotic Killing vectors,which could not be determined through the effective action approach,contribute to the central charge as well.We also show that the boundary conditions suggested by Guica et al.[Phys.Rev.D 80 (2009)124008] lead to a divergent first-order boundary effective action.
