Single Interval R\'enyi Entropy At Low Temperature

TL;DR

This paper computes the R'enyi entropy for a single interval at low temperature in 2D CFT, comparing field theory and holographic results, and confirms their agreement in the large central charge limit.

Contribution

It extends previous analyses by calculating higher-order terms and fixing constants in holographic R'enyi entropy, providing further evidence for the AdS3/CFT2 correspondence with thermal effects.

Findings

Field theory and holographic results agree at higher orders

Explicit calculation of low-temperature expansion terms

Confirmation of holographic R'enyi entropy validity with thermal effects

Abstract

In this paper, we calculate the R\'enyi entropy of one single interval on a circle at finite temperature in 2D CFT. In the low temperature limit, we expand the thermal density matrix level by level in the vacuum Verma module, and calculate the first few leading terms in $e^{-\pi/TL}$ explicitly. On the other hand, we compute the same R\'enyi entropy holographically. After considering the dependence of the R\'enyi entropy on the temperature, we manage to fix the interval-independent constant terms in the classical part of holographic R\'enyi entropy. We furthermore extend the analysis in Xi Dong's paper to higher orders and find exact agreement between the results from field theory and bulk computations in the large central charge limit. Our work provides another piece of evidence to support holographic computation of R\'enyi entropy in AdS$_3$/CFT$_2$ correspondence, even with thermal effect.