D-Brane Probe and Closed String Tachyons

TL;DR

This paper investigates the dynamics of D-brane probes in unstable string backgrounds with fluxes, revealing nonlocal Yang-Mills behavior and exploring the decay of closed string tachyons in various orbifold models.

Contribution

It introduces a novel setup to study unstable closed string theories via D-brane probes, linking spacetime twists to nonlocal gauge theories and analyzing tachyon couplings.

Findings

Open Wilson lines mix with adjoint matter phases due to spacetime twist.

The probe dynamics form a nonlocal, nonsupersymmetric Yang-Mills theory.

Discussion of closed string tachyon couplings in orbifold limits.

Abstract

We consider a D-brane probe in unstable string background associated with flux branes. The twist in spacetime metric reponsible for the supersymmetry breaking is shown to manifest itself in mixing of open Wilson lines with the phases of some adjoint matter fields, resulting in a nonlocal and nonsupersymmetric form of Yang-Mills theory as the probe dynamics. This provides a setup where one can study fate of a large class of unstable closed string theories that include as a limit type 0 theories and various orbifolds of type II and type 0 theories. We discuss the limit of ${\bf C}/Z_n$ orbifold in some detail and speculate on couplings with closed string tachyons.