A Note on Tachyon Moduli and Closed Strings

TL;DR

This paper investigates the collective behavior of brane states in non-critical string theory, revealing connections to coset models, tachyon condensation, and closed string spectra, with implications for understanding string vacua and limits.

Contribution

It introduces a new limit inspired by tachyon condensation that aligns the spectrum with two-dimensional string theory, expanding the understanding of string vacua and collective brane dynamics.

Findings

Brane states mimic the coset WZW model.

A new limit reproduces the spectrum of 2D string theory.

Connections between different vacuum interpretations are observed.

Abstract

The collective behavior of the SL(2,R) covariant brane states of non-critical c=1 string theory found in a previous work, is studied in the Fermi liquid approximation. It is found that such states mimick the coset WZW model, whereas only by further restrictions one recovers the double-scaling limit which was purported to be equivalent to closed string models. Another limit is proposed, inspired by the tachyon condensation ideas, where the spectrum is the same of two-dimensional string theory. We close by noting some strange connections between vacuum states of the theory in their different interpretations.