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Thermal spectral function asymptotics and black hole singularity in holography

Hewei Frederic Jia, Mukund Rangamani

TL;DR

Addressing how thermal spectral functions in holographic CFTs encode black hole interior data, the paper develops a transseries description of non-perturbative corrections at large momentum. It demonstrates a factorization of the spectral function for special integer-dimension operators into a vacuum piece and a non-perturbative piece, whose asymptotics are governed by a momentum-dependent transseries derived from exact WKB and Virasoro-block monodromy. The analysis yields explicit formulae for the non-perturbative piece, including a leading exponential structure and Voros-symbol-based monodromy, connecting to singularities in the complex time plane of thermofield correlators. The results extend previous radial-limit insights to finite momentum and clarify how the black hole singularity may be reflected in real-time correlators, while highlighting the need for a deeper geometric interpretation beyond Δ ~ O(1).

Abstract

We investigate the analytic structure of thermal spectral function of holographic CFTs, synthesizing recent developments into a set of observations about its asymptotics. Specifically, for a class of scalar primaries with integral dimension, we demonstrate factorization of the exact spectral function into a polynomial piece, which captures the vacuum dynamics, and a non-perturbative piece, which controls its asymptotics. Using exact WKB techniques, we derive a transseries expression for the latter. We use this information to deduce the singular loci of a spatially averaged thermofield double correlator in the complex time plane. Such singularities have been argued to encode information regarding the black hole singularity in the dual spacetime. Our results give a refinement of these statements by capturing the momentum dependence.

Thermal spectral function asymptotics and black hole singularity in holography

TL;DR

Addressing how thermal spectral functions in holographic CFTs encode black hole interior data, the paper develops a transseries description of non-perturbative corrections at large momentum. It demonstrates a factorization of the spectral function for special integer-dimension operators into a vacuum piece and a non-perturbative piece, whose asymptotics are governed by a momentum-dependent transseries derived from exact WKB and Virasoro-block monodromy. The analysis yields explicit formulae for the non-perturbative piece, including a leading exponential structure and Voros-symbol-based monodromy, connecting to singularities in the complex time plane of thermofield correlators. The results extend previous radial-limit insights to finite momentum and clarify how the black hole singularity may be reflected in real-time correlators, while highlighting the need for a deeper geometric interpretation beyond Δ ~ O(1).

Abstract

We investigate the analytic structure of thermal spectral function of holographic CFTs, synthesizing recent developments into a set of observations about its asymptotics. Specifically, for a class of scalar primaries with integral dimension, we demonstrate factorization of the exact spectral function into a polynomial piece, which captures the vacuum dynamics, and a non-perturbative piece, which controls its asymptotics. Using exact WKB techniques, we derive a transseries expression for the latter. We use this information to deduce the singular loci of a spatially averaged thermofield double correlator in the complex time plane. Such singularities have been argued to encode information regarding the black hole singularity in the dual spacetime. Our results give a refinement of these statements by capturing the momentum dependence.

Paper Structure

This paper contains 6 sections, 21 equations, 1 figure.

Figures (1)

  • Figure 1: The Stokes graphs for \ref{['eq:Qpot']} in the timelike regime $0<\zeta <1$ with $\vartheta = \arg(\mathfrak{w}) = \arg(\mathfrak{q})$. The thick black lines are Stokes lines that demarcate the different Stokes regions on the $u$ plane. The turning points, singularities, placement of branch cuts, monodromy contours $\mathcal{C}_{0,1}$ centered at base point $u_0$, and the A and B cycles are indicated for reference.