The spectral function in a strongly coupled, thermalising CFT

TL;DR

This paper investigates the time-dependent spectral function and effective temperature in a thermalising two-dimensional conformal field theory using holographic duality, extending previous work to dynamic, non-equilibrium settings.

Contribution

It extends the calculation of spectral functions and effective temperatures to a time-dependent, thermalising CFT dual to AdS3-Vaidya spacetime, employing geodesic approximation and novel analytic continuation methods.

Findings

Computed spectral functions during thermalisation process

Demonstrated evolution of effective temperature over time

Extended holographic techniques to non-equilibrium dynamics

Abstract

In relation to the fluctuation-dissipation theorem, we discuss a time-dependent notion of spectral function and effective temperature. Extending recent results from arXiv:1212.6066, we work out these quantities in a two-dimensional thermalising CFT dual to AdS3-Vaidya spacetime which interpolates between a black brane geometry at early times and a higher temperature black brane at late times. The computation is carried out in the gravitational holographic dual in the geodesic approximation and using a non-standard analytic continuation.