Long Strings, Anomaly Cancellation, Phase Transitions, T-duality and Locality in the 2d Heterotic String

TL;DR

This paper investigates the dynamics of noncritical 2D heterotic strings, highlighting the role of long strings in anomaly cancellation, phase transitions, and the interplay between T-duality and locality upon compactification.

Contribution

It uncovers new subtleties in gauge symmetries affecting worldsheet results and explores the incompatibility between T-duality and locality in thermal compactifications.

Findings

Long strings cancel anomalies in 2D heterotic strings.

Phase transitions occur during circle compactification.

T-duality conflicts with locality in thermal settings.

Abstract

We study the noncritical two-dimensional heterotic string. Long fundamental strings play a crucial role in the dynamics. They cancel anomalies and lead to phase transitions when the system is compactified on a Euclidean circle. A careful analysis of the gauge symmetries of the system uncovers new subtleties leading to modifications of the worldsheet results. The compactification on a Euclidean thermal circle is particularly interesting. It leads us to an incompatibility between T-duality (and its corresponding gauge symmetry) and locality.