A Proposal for Altering the Unification Scale in String Theory

TL;DR

This paper proposes a mechanism within string theory where a thermal phase transition of open strings near D-branes can modify the unification scale of fundamental forces, potentially impacting grand unified theories.

Contribution

It introduces a novel thermal phase transition process that can alter the unification scale in string theory models with electromagnetic backgrounds.

Findings

Thermal phase transition occurs just below the string scale.

Open string ensemble undergoes a transition to a long string phase.

Mechanism allows changing the unification scale relative to the fundamental string scale.

Abstract

An ensemble of short open strings in equilibrium with the heat bath provided by the Euclidean worldvolume of a stack of Dbranes undergoes a thermal phase transition to a long string phase. The transition temperature is just below the string scale. We point out that this phenomenon provides a simple mechanism within open and closed string theories for altering the strong-electro-weak coupling unification scale relative to the fundamental closed string mass scale in spacetimes with external electromagnetic background.