The open string pair-production rate enhancement by a magnetic flux

TL;DR

This paper extends amplitude calculations for D-branes with fluxes, revealing that magnetic flux can significantly enhance open string pair production rates, especially when fluxes share no common indices.

Contribution

It generalizes previous amplitude calculations to new flux configurations and demonstrates the magnetic flux's role in greatly increasing pair production rates.

Findings

Pair production rate is greatly enhanced by magnetic flux.

Enhancement occurs when fluxes share no common index.

Significant effects at string-scale separations.

Abstract

We extend the amplitude calculations of \cite{Lu:2009yx} to exhaust the remaining cases for which one set of D$_p$ branes carrying a flux (electric or magnetic) is placed parallel at separation to the other set carrying also a flux but with the two fluxes sharing at most one common field-strength index. We then find that the basic structure of amplitudes remains the same when the two fluxes share at least one common index but it is more general when the two fluxes share no common index. We discuss various properties of the amplitudes such as the large separation limit, the onset of various instabilities and the open string pair production. In particular, when one flux is electric and weak and the other is magnetic and fixed, we find that the open string pair production rate is greatly enhanced by the presence of this magnetic flux when the two fluxes share no common field-strength index and this rate becomes significant when the separation is on the order of string scale.