String Loop Corrections to Stable Non-BPS Branes

TL;DR

This paper computes string loop corrections to the tachyon potential for stable non-BPS D-branes, revealing phase structures and attraction behaviors, with divergences for certain branes addressed via regularization techniques.

Contribution

It provides the first detailed calculation of loop corrections to the tachyon potential for non-BPS D-branes on orbifolds, including phase analysis and divergence regularization.

Findings

Non-trivial phase structure in tachyon potential

Attraction between non-BPS Dp-branes for p=0,1,2 after tachyon condensation

Divergences for p=3,4 explained and regularized

Abstract

We calculate the string loop corrections to the tachyon potential for stable non-BPS Dp-branes on the orbifold T^4/Z_2. We find a non-trivial phase structure and we show that, after tachyon condensation, the non-BPS Dp-branes are attracted to each other for p=0,1,2. We then identify the corresponding closed string boundary states together with the massless long range fields they excite. For p=3,4 the string loop correction diverge. We identify the massless closed string fields responsible for these divergencies and regularise the partition function using a Fischler-Susskind mechanism.