Analytic Study for the String Theory Landscapes via Matrix Models

TL;DR

This paper uses matrix models to analyze string theory landscapes, revealing stability properties of various vacua and identifying ghost D-instantons as sources of instability in tachyon-less closed string theories.

Contribution

It provides a first-principle non-perturbative analysis of string vacua stability using matrix models, highlighting the role of ghost D-instantons.

Findings

Pure gravity vacuum is stable.

Yang-Lee edge singularity vacuum is false.

Most minimal string vacua are unstable.

Abstract

We demonstrate a first-principle analysis of the string theory landscapes in the framework of non-critical string/matrix models. In particular, we discuss non-perturbative instability, decay rate and the true vacuum of perturbative string theories. As a simple example, we argue that the perturbative string vacuum of pure gravity is stable; but that of Yang-Lee edge singularity is inescapably a false vacuum. Surprisingly, most of perturbative minimal string vacua are unstable, and their true vacuum mostly does not suffer from non-perturbative ambiguity. Importantly, we observe that the instability of these tachyon-less closed string theories is caused by ghost D-instantons (or ghost ZZ-branes), the existence of which is determined only by non-perturbative completion of string theory.