Regular Black Holes: Entropy Products and Central Charges

In this paper for variety types of regular black hole solutions, we investigate the entropy product of inner and outer horizons. Similar to singular black holes, for the regular ones we find that universality (mass independence) of the entropy product is true for some solutions and it fails for some others. In the case of regular black holes that respect the universality, we read central charges of the dual CFTs from the entropy product, according to the Thermodynamics method introduced in \cite{Chen:2013rb}. For these solutions we also calculate central charges, using the asymptotic symmetry group formalism. The results of these two approaches are the same, which means that universality of the entropy product provides a simple method to find central charges of the dual CFTs.Comment: minor correction

More on Five Dimensional EVH Black Rings

In this paper we continue our analysis of arXiv:1308.1478[hep-th] and study in detail the parameter space of three families of doubly spinning black ring solutions: balanced black ring, unbalanced ring and dipole-charged balanced black rings. In all these three families the Extremal Vanishing Horizon (EVH) ring appears in the vanishing limit of the dimensionful parameter of the solution which measures the ring size. We study the near horizon limit of the EVH black rings and for all three cases we find a (pinching orbifold) AdS$_3$ throat with the AdS$_3$ radius $\ell^2=8 G_5 M/(3\pi)$ where $M$ is the ring mass and $G_5$ is the 5d Newton constant. We also discuss the near horizon limit of near-EVH black rings and show that the AdS$_3$ factor is replaced with a generic BTZ black hole. We use these results to extend the EVH/CFT correspondence for black rings, a 2d CFT dual to near-EVH black rings.Comment: 30 page

Central charges from Thermodynamics method in 3D gravity

In the context of guage/gravity duality, we investigate the central charges of a number of 2-dimensional conformal field theories (CFTs) that might live on the boundary of some 3-dimensional (3D) toy models of gravity, from the thermodynamics aspect of the black holes. For many black hole solutions, the entropy product of the inner Cauchy and outer event horizons is universal (mass independent). It is proposed that for these solutions, the central charges of the left- and right-moving sectors of the dual CFTs should be the same and one may read the central charges from the universal entropy product. This provides strong motivations for investigating this prescription for BTZ and Warped AdS$_{3}$ black holes in a number of 3D gravity theories and we will show that the proposal works truly. One striking result of our analysis is that if the entropy product is not universal in any theory of 3D gravity, then the left and right central charges are not equal.Comment: 19 pages, Accepted version. arXiv admin note: text overlap with arXiv:1906.00993 by other author

On higher derivative corrections of tachyon action

We have examined the momentum expansion of the disk level S-matrix element of two tachyons and two gauge fields to find, up to on-shell ambiguity, the couplings of these fields in the world volume theory of N coincident non-BPS D-branes to all order of $\alpha'$. Using the proposal that the action of D-brane-anti-D-brane is given by the projection of the action of two non-BPS D-branes with $(-1)^{F_L}$, we find the corresponding couplings in the world volume theory of the brane-anti-brane system. Using these infinite tower of couplings, we then calculate the massless pole of the scattering amplitude of one RR field, two tachyons and one gauge field in the brane-anti-brane theory. We find that the massless pole of the field theory amplitude is exactly equal to the massless pole of the disk level S-matrix element of one RR, two tachyons and one gauge field to all order of $\alpha'$.Comment: 22 pages, 1 figure, latex file, V2: minor change in notatio