Double Field Theory for Double D-branes

TL;DR

This paper develops a T-duality covariant effective field theory for double D-branes using Hull's doubled formalism, unifying T-dual configurations through a master DBI action.

Contribution

It constructs a T-duality covariant double field theory for D-branes, providing a unified description of T-dual configurations via a master DBI action.

Findings

Derived the boundary conditions for double D-branes in doubled formalism.

Formulated a T-duality covariant DBI action for double D-branes.

Showed the effective theory unifies T-dual D-brane configurations.

Abstract

We consider Hull's doubled formalism for open strings on D-branes in flat space and construct the corresponding effective double field theory. We show that the worldsheet boundary conditions of the doubled formalism describe in a unified way a T-dual pair of D-branes, which we call double D-branes. We evaluate the one-loop beta function for the boundary gauge coupling and then obtain the effective field theory for the double D-branes. The effective field theory is described by a DBI action of double fields. The T-duality covariant form of this DBI action is thus a kind of "master" action, which describes all the double D-brane configurations related by T-duality transformations. We discuss a number of aspects of this effective theory.