Discrete States in Light-Like Linear Dilaton Background

TL;DR

This paper investigates the spectrum of bosonic strings in a light-like linear dilaton background, revealing discrete states that are linked to spacetime symmetries and suggesting a broader concept of symmetry in string theory.

Contribution

It identifies and characterizes discrete states in a light-like linear dilaton background, highlighting their role in spacetime symmetries and proposing a generalized notion of symmetry.

Findings

Discrete states exist only at specific momenta

Most discrete states generate spacetime symmetries

One state corresponds to deformations of conservation laws

Abstract

We study the spectrum of bosonic strings in the light-like linear dilaton background and find discrete states. These are physical states which exist only at specific values of momentum. All except one discrete states generate spacetime symmetries. The exceptional discrete state corresponds to constraints which are deformations of conservation laws. The constraints resemble those arising from symmetries, and are equally powerful, suggesting that our notion of symmetry should be generalized.