Supersymmetric Boost on Intersecting D-branes

TL;DR

This paper investigates how electric and magnetic fields, as well as boosts, affect the supersymmetry of intersecting D-branes, revealing conditions under which various amounts of supersymmetry are preserved.

Contribution

It provides a detailed analysis of supersymmetry preservation in intersecting D-branes under electric/magnetic fields and Lorentz boosts, including new conditions for supersymmetry retention.

Findings

Electric fields do not affect supersymmetry unless approaching a critical value.

Magnetic fields and boosts can preserve up to 8 supersymmetries under specific conditions.

Supersymmetry preservation depends on the orientation, velocity, and intersecting angles of D-branes.

Abstract

We study the effect of the Born-Infeld electric field on the supersymmetric configuration of various composite D-branes. We show that the generic values of the electric field do not affect the supersymmetry but, as it approaches $1/2\pi\alpha'$ keeping the magnetic field finite, various combinations of the magnetic fields allow up to 8 supersymmetries. We also explore the unbroken supersymmetries for two intersecting D-strings which are in uniform or relative motion. For a finite uniform Lorentz boost, 16 supersymmetries are guaranteed only when they are parallel. For an infinite one, 8 supersymmetries are preserved only when both the D-strings are oriented to the forward or backward direction of the boost. Under a finite relative boost, 8 supersymmetries are preserved only when the intersecting angle is less than $\pi/2$ and the intersecting point moves at the speed of light. As for an infinite relative boost, 8 supersymmetries are preserved regardless of the values of the intersecting angle.