A note on the stability of axionic D-term strings

TL;DR

This paper studies the stability of a new class of BPS cosmic strings in supergravity, revealing that certain zero modes can lead to spacetime decompactification over time, with implications for string theory models.

Contribution

It introduces and analyzes the stability of axionic D-term strings, a novel class of solutions in supergravity linked to string theory, and explores their dynamical evolution.

Findings

Zero mode in axionic strings can be excited.

Excitation leads to decompactification of spacetime.

Decompactification rate decreases with lower brane tension.

Abstract

We investigate the stability of a new class of BPS cosmic strings in N=1 supergravity with D-terms recently proposed by Blanco-Pillado, Dvali and Redi. These have been conjectured to be the low energy manifestation of D-strings that might form from tachyon condensation after D- anti-D-brane annihilation in type IIB superstring theory. There are three one-parameter families of cylindrically symmetric one-vortex solutions to the BPS equations (tachyonic, axionic and hybrid). We find evidence that the zero mode in the axionic case, or s-strings, can be excited. Its evolution leads to the decompactification of four-dimensional spacetime at late times, with a rate that decreases with decreasing brane tension.