Universal sectors of two-dimensional Carrollian CFTs

TL;DR

This paper explores modular invariance in 2D Carrollian CFTs, identifying sectors with vacuum dominance and their holographic interpretations, including a Schwarzian-like sector with negative specific heat linked to flat space horizons.

Contribution

It introduces a geometric approach to modular invariance in Carrollian CFTs, revealing new sectors with vacuum dominance and their holographic significance.

Findings

Identification of vacuum-dominant sectors in dual channels

Existence of a Schwarzian-like sector with flat space holography

Negative specific heat in sectors with vacuum dominance

Abstract

We revisit modular invariance in two-dimensional Carrollian conformal field theories from a geometric perspective. Focusing on the characters of the induced and highest-weight representations of the theory, we show that there are regions of parameter space where the vacuum character dominates in the dual channel. We use this property to zoom into different subsectors of the Carrollian theory. One of them is reminiscent of the Schwarzian sector of a relativistic CFT2 and has a flat space holographic interpretation as O-plane orbifold. It exists only for the highest-weight representation. We prove that for all sectors with vacuum dominance in the dual channel, the specific heat is negative, concurrent with the holographic interpretation of the negative specific heat of asymptotically flat spacetimes with horizons.