On the Production of Open Strings from Brane Anti-Brane Annihilation

TL;DR

This paper analyzes open string production during brane anti-brane annihilation using BCFT, revealing a finite total amplitude after summing over oscillator levels, with implications for brane inflation reheating.

Contribution

It provides a detailed 1-loop BCFT calculation showing how to obtain finite open string production amplitudes in time-dependent brane backgrounds.

Findings

Naive divergence in single oscillator level amplitude is resolved by summing over all levels.

The inverse Wick rotation point is clarified for these calculations.

Results have potential implications for reheating in brane inflation models.

Abstract

We investigate the leading contribution to open string production in the time dependent background of the Brane Anti-Brane. This is a 1-loop diagram and we use Boundary Conformal Field Theory (BCFT) techniques to study it. We show that the amplitude to a single open string naively diverges when one looks at it as an expansion in oscillator levels. Nevertheless, we show that once we sum over all oscillator levels we get a finite result. We also clarify where to perform the inverse Wick rotation in this kind of problems. This calculation could have important consequences for the theory of reheating in brane inflationary models.