Quasinormal modes and holographic correlators in a crunching AdS geometry

Abstract

We calculate frequency space holographic correlators in an asymptotically AdS crunching background, dual to a relevant deformation of the M2-brane CFT placed in de Sitter spacetime. For massless bulk scalars, exploiting the connection to a solvable supersymmetric quantum mechanical problem, we obtain the exact frequency space correlator for the dual operator in the deformed CFT. Controlling the shape of the crunching surface in the Penrose diagram by smoothly dialling the deformation from zero to infinity, we observe that in the large deformation limit the Penrose diagram becomes a 'square', and the exact holographic correlators display striking similarities to their counterparts in the BTZ black hole and its higher dimensional generalisations. We numerically determine quasinormal poles for relevant and irrelevant operators, and find an intricate pattern of these in the complex frequency plane. In the case of relevant operators, the deformation parameter has an infinite sequence of critical values, each one characterised by a pair of poles colliding and moving away from the imaginary frequency axis with increasing deformation. In the limit of infinite deformation all scalar operators have identical quasinormal spectra. We compare and contrast our strongly coupled de Sitter QFT results with strongly coupled thermal correlators from AdS black holes.

The CST bounce universe model — A parametric study

“…Recently an interesting attempt is made to use AdS/CFT correspondence to study the evolution of matter through the bounce point [46] which is inspired by an earlier attempt of using AdS/CFT to study cosmic singularity in the bound universe [45]. Pioneer works on studying AdS singularity can be found in [47][48][49][50][51][52][53][54], together with earlier initiatives of using AdS/CFT to study cosmic singularities [55][56][57][58][59][60][61][62][63][64][65][66]. A thorough study of physics in the bounce universe is in sight.…”

Nonequilibrium dynamics of the O(N ) model on dS3 and AdS crunches

“…This work was motivated by the existence of gravity duals of de Sitter space QFTs at large-N , obtained by relevant deformations of (known) CFTs yielding bulk crunch singularities in the holographic duals (e.g. [4,7,10,11]). Our goal was to understand whether the E-frame evolution of such QFTs is always singular.…”

“…an approach to a conformal point and appearance of higher spin currents may be necessary to avoid bulk crunch singularities within a dual gravitational setting. This is of particular relevance to FRW crunch singularities occurring within supergravity duals of large-N CFTs placed in de Sitter spacetime with relevant operators turned on (and with a stable ground state for the resulting theory) [7,10,11]. Within Einstein gravity, the theorem of Abbott and Coleman [30] implies that any deformation of (dSsliced) AdS will lead to a crunch singularity.…”

“…Intriguingly, there exist several examples of asymptotically AdS backgrounds exhibiting an FRW crunch singularity, dual to deformations of large-N CFTs placed in de Sitter spacetime [4][5][6][7][8][9][10][11]. Such "crunching-AdS" geometries arise in de-Sittersliced, asymptotically AdS spacetimes where the crunch singularity is cloaked behind a bulk horizon.…”

“…Various approaches towards answering this and similar questions have been proposed and investigated [5,6,8,9,[12][13][14][15][16][17] from both QFT and holographic perpsectives. Holographic probes of such geometries and the associated bulk singularities have also been considered in order to arrive at a precise interpretation of the singularities [10,11,18,19], inspired by analogous investigations of the black hole singularity in AdS/CFT [20,21].…”