Holographic Signatures of Cosmological Singularities

Abstract

To gain insight into the quantum nature of cosmological singularities, we study anisotropic Kasner solutions in gauge/gravity duality. The dual description of the bulk evolution towards the singularity involves N = 4 super Yang-Mills on the expanding branch of deformed de Sitter space and is well defined. We compute two-point correlators of Yang-Mills operators of large dimensions using spacelike geodesics anchored on the boundary. The correlators show a strong signature of the singularity around horizon scales and decay at large boundary separation at different rates in different directions. More generally, the boundary evolution exhibits a process of particle creation similar to that in inflation. This leads us to conjecture that information on the quantum nature of cosmological singularities is encoded in long-wavelength features of the boundary wave function.

Holographic Van der Waals phase transition of the higher-dimensional electrically charged hairy black hole

“…In recent years, the twopoint correlation function has appeared to be a useful tool which can be used to explore some physical phenomena such as holographic singularities [29,30], holographic thermalization [31,32], holographic CFTs on maximally symmetric spaces [33], holographic butterfly effect [34][35][36][37] and quantum phase transition [38]. Motivated by the above-mentioned issues, we attempt to detect whether the two-point correlation function can present a Van der Waals-like behavior for the charged hairy black hole.…”

Probing crunching AdS cosmologies

“…This is clear in Euclidean signature following a coordinate change, 10) whereξ and the conformal factor Λ are determined by solving the differential equations:…”

“…The implication of the behaviour of such probe geodesics for frequency space (thermal) Wightman functions was worked out precisely in [13] applying a WKB approximation to wave equations in the bulk. The general idea of probing bulk singularities with correlators in the geodesic limit has proved to be extremely attractive and has been applied recently to deduce a direct signature of singularities in anisotropic Kasner-AdS solutions within the holographic setting [10,11,14].…”

“…Several important advances in this direction have been made, within the general framework of strings and holography, e.g. [3][4][5], and through the embedding of cosmological crunching geometries in Anti-de Sitter (AdS) spacetime [6][7][8][9], and more recently in [10,11]. The main goal in a holographic setting of this type is to find out how a given bulk (cosmological) singularity makes itself known within the dual quantum field theory.…”

Towards timelike singularity via AdS dual

“…We pursue the approach undertaken in [10,11,12]. Using the geodesic approximations we compute the two-point correlators for largely massive operators.…”