Kasner eons with matter: holographic excursions to the black hole singularity

TL;DR

This paper explores how matter influences the sequence of Kasner eons near singularities in higher-curvature gravity theories and examines their holographic signatures within black hole interiors.

Contribution

It demonstrates the significant impact of matter on Kasner eons and investigates their observable effects in holographic duals of black holes.

Findings

Matter alters the physics of Kasner eons compared to vacuum cases.

Holographic observables like the $a$-function and two-point functions reveal signatures of eons.

Holographic complexity can diagnose stringy effects near black hole singularities.

Abstract

Recent work has shown that introducing higher-curvature terms to the Einstein-Hilbert action causes the approach to a space-like singularity to unfold as a sequence of Kasner eons. Each eon is dominated by emergent physics at an energy scale controlled by higher-curvature terms of a given order, transitioning to higher-order eons as the singularity is approached. The purpose of this paper is twofold. First, we demonstrate that the inclusion of matter dramatically modifies the physics of eons compared to the vacuum case. We illustrate this by considering a family of quasi-topological gravities of arbitrary order minimally coupled to a scalar field. Second, we investigate Kasner eons in the interior of black holes with field theory duals and analyze their imprints on holographic observables. We show that the behavior of the thermal $a$-function, two-point functions of heavy operators, and holographic complexity can capture distinct signatures of the eons, making them promising tools for diagnosing stringy effects near black hole singularities.