Fake gaps in AdS_3/CFT_2

TL;DR

This paper explores how holography reflects the impossibility of gapping systems with chiral anomalies in AdS3/CFT2, analyzing spectra and entanglement entropy to demonstrate the absence of a mass gap.

Contribution

It shows how holography captures the robust feature that systems with chiral anomalies cannot be gapped, using spectral and entanglement entropy analysis.

Findings

No mass gap exists in the presence of a chiral anomaly.

Linearized spectrum analysis confirms gaplessness.

Holographic entanglement entropy supports the absence of a gap.

Abstract

We discuss properties of interpolating geometries in three dimensional gravity in the presence of a chiral anomaly. This anomaly, which introduces an unbalance between left and right central charges, is protected under RG flows. For this simple reason it is impossible to gap a system with such an anomaly. Our goal is to discuss how holography captures this basic and robust feature. We demonstrate the absence of a mass gap by analysing the linearized spectrum and holographic entanglement entropy of these backgrounds in the context of AdS$_3$/CFT$_2$.