Boundary Carrollian CFTs and Open Null Strings

TL;DR

This paper develops boundary Carrollian conformal algebras in two dimensions, constructs open null strings with Dirichlet boundary conditions, and relates these to contractions of the Virasoro algebra, expanding the understanding of Carrollian symmetries.

Contribution

It introduces the boundary Carrollian conformal algebra, constructs open null strings with boundary conditions, and links these to Virasoro algebra contractions, providing new insights into Carrollian symmetries.

Findings

BCCA emerges from contracting a Virasoro algebra.

Open null strings with Dirichlet conditions realize BCCA.

Null limit of tensile strings reproduces the string results.

Abstract

We consider Carrollian conformal field theories in two dimensions and construct the boundary Carrollian conformal algebra (BCCA), opening up innumerable possibilities for further studies, given the growing relevance of Carrollian symmetries. We prove that the BCCA emerges by contracting a single copy of the Virasoro algebra. As an application, we construct, for the first time, open null strings and show that, for Dirichlet boundary conditions, we recover the BCCA as the algebra of constraints. We finally reconstruct our string results by taking the null limit of tensile open strings.