Strings and D-branes in a supersymmetric magnetic flux background

TL;DR

This paper studies how RR magnetic fluxes influence the energy and supersymmetry of Dp branes in string theory backgrounds, revealing that magnetic fields can lower brane energies and preserve supersymmetry.

Contribution

It introduces a class of BPS solutions in magnetic flux backgrounds, showing magnetic fields can reduce brane energies without breaking supersymmetry.

Findings

Magnetic fields can significantly lower the energy of certain BPS branes.

Some macroscopic Dp branes become light under strong magnetic fields.

Supersymmetry remains intact despite magnetic flux influence.

Abstract

We investigate how the presence of RR magnetic $F_{p+2}$ fluxes affects the energy of classical Dp branes, for specific string theory supersymmetric backgrounds which are solutions to the leading order in $\alpha'$ including back-reaction effects. The Dp brane dynamics is found to be similar to the well known dynamics of particles and strings moving in magnetic fields. We find a class of BPS solutions which generalize the BPS fundamental strings or BPS branes with momentum and winding to the case of non-zero magnetic fields. Remarkably, the interaction with the magnetic fields does not spoil the supersymmetry of the solution, which turns out to be invariant under four supersymmetry transformations. We find that magnetic fields can significantly reduce the energy of some BPS strings and Dp branes, in particular, some macroscopic Dp branes become light for sufficiently large magnetic fields.