Universality of Nonperturbative Effect in Type 0 String Theory

TL;DR

This paper investigates the nonperturbative effects in type 0B string theory via matrix models, revealing a universal instanton contribution that relates to D-brane instability.

Contribution

It demonstrates the universality of the instanton contribution in type 0 string theory's matrix model, independent of potential details, and links it to D-brane instability.

Findings

The instanton contribution's overall factor is universal.

The factor is purely imaginary, indicating D-brane instability.

The string equation alone cannot fully determine nonperturbative effects.

Abstract

We derive the nonperturbative effect in type 0B string theory, which is defined by taking the double scaling limit of a one-matrix model with a two-cut eigenvalue distribution. However, the string equation thus derived cannot determine the nonperturbative effect completely, at least without specifying unknown boundary conditions. The nonperturbative contribution to the free energy comes from instantons in such models. We determine by direct computation in the matrix model an overall factor of the instanton contribution, which cannot be determined by the string equation itself. We prove that it is universal in the sense that it is independent of the detailed structure of potentials in the matrix model. It turns out to be a purely imaginary number and therefore can be interpreted as a quantity related to instability of the D-brane in type 0 string theory. We also comment on a relation between our result and boundary conditions for the string equation.