The principle of least action and the geometric basis of D-branes

TL;DR

This paper provides a geometric and intrinsic foundation for D-branes in classical non-linear sigma models, defining their properties in complex flux backgrounds and within other D-branes, based on boundary conditions.

Contribution

It derives the geometric objects corresponding to D-branes from first principles, extending their definition to flux backgrounds and nested configurations.

Findings

Classical D-branes are given an intrinsic geometric foundation.

D-branes in nontrivial H flux are precisely defined.

D-branes embedded within other D-branes are characterized explicitly.

Abstract

We analyze thoroughly the boundary conditions allowed in classical non-linear sigma models and derive from first principle the corresponding geometric objects, i.e. D-branes. In addition to giving classical D-branes an intrinsic and geometric foundation, D-branes in nontrivial H flux and D-branes embedded within D-branes are precisely defined. A well known topological condition on D-branes is replaced.