Interaction of Discrete States in Two-Dimensional String Theory

TL;DR

This paper investigates the couplings of discrete states in two-dimensional string theory, revealing their structure constants relate to area-preserving diffeomorphisms and proposing an invariant effective action.

Contribution

It introduces a novel effective action for discrete states in 2D string theory that respects the infinite-dimensional symmetry group of area-preserving diffeomorphisms.

Findings

Couplings correspond to structure constants of area-preserving diffeomorphisms

An invariant effective action for discrete states is proposed

The symmetry group is infinite-dimensional

Abstract

We study the couplings of discrete states that appear in the string theory embedded in two dimensions, and show that they are given by the structure constants of the group of area preserving diffeomorphisms. We propose an effective action for these states, which is itself invariant under this infinite-dimensional group.