Dielectric-Branes

TL;DR

This paper extends the world-volume action for multiple Dp-branes to include nonabelian gauge theories, revealing new couplings and polarization effects, such as D0-branes expanding into a D2-brane in external fields.

Contribution

It provides a T-duality consistent nonabelian Dp-brane action with potential terms and demonstrates polarization phenomena like D0-branes forming D2-branes in background fields.

Findings

D0-branes expand into a noncommutative sphere in RR fields

The action includes couplings to all RR potential forms

Polarization effects demonstrate brane bound state formation

Abstract

We extend the usual world-volume action for a Dp-brane to the case of N coincident Dp-branes where the world-volume theory involves a U(N) gauge theory. The guiding principle in our construction is that the action should be consistent with the familiar rules of T-duality. The resulting action involves a variety of potential terms, i.e., nonderivative interactions, for the nonabelian scalar fields. This action also shows that Dp-branes naturally couple to RR potentials of all form degrees, including both larger and smaller than p+1. We consider the dynamics resulting from this action for Dp-branes moving in nontrivial background fields, and illustrate how the Dp-branes are ``polarized'' by external fields. In a simple example, we show that a system of D0-branes in an external RR four-form field expands into a noncommutative two-sphere, which is interpreted as the formation of a spherical D2-D0 bound state.