Regular Seminar Francesco Benini (SISSA, Trieste)
AdS/CFT provides a consistent non-perturbative definition of quantum gravity in asymptotically AdS space. Black holes should correspond to ensembles of states in the boundary field theory. By analyzing the superconformal index of 4d N=4 SU(N) Super-Yang-Mills, with the help of a new Bethe Ansatz type formula, we are able to exactly reproduce the Bekenstein-Hawking entropy of BPS black holes in AdS5 x S5. The large N limit exhibits many competing contributions and Stokes phenomena, hinting at new physics.
Regular Seminar Karapet Mkrtchyan (Potsdam)
We study the possibility for a unitary theory of partially-massless (PM) spin-two field interacting with Gravity in arbitrary dimensions. We show that parity invariant interactions respecting general covariance lead to a reconstruction of Conformal Gravity in even dimensions. In this case the unitarity is sacrificed. By relaxing the parity invariance, we find a possibility of a unitary theory in four dimensions, but the parity-odd cubic vertex cannot be written in usual metric variables. We comment on possible approaches that may allow for the formulation of this theory. Finally, by relaxing the general covariance, we show that a non-minimal coupling between massless and PM spin-two fields may lead to an alternative possibility of a unitary theory, that necessarily involves mixed-symmetry fields.
Regular Seminar Matthew Roberts (Imperial)
room G O Jones 610
We construct new supersymmetric solutions of 11D supergravity, preserving 1/4 of the supersymmetry, that are dual to the ABJM Chern-Simons-matter theory deformed by mass terms which depend on one spatial direction. The BPS equations boil down to solving the Helmholtz equation on the complex plane giving rise to rich classes of new solutions. In particular, the construction gives rise to infinite classes of new supersymmetric “boomerang” RG flows, as well as generalising other previously known solutions.