Brane Transfer Operations and T-Duality of Non-BPS States

TL;DR

This paper explores how T-duality affects non-BPS D-branes in various string theory compactifications using K-theory, revealing charge transfer phenomena and stability conditions influenced by orientifold planes.

Contribution

It demonstrates the role of relative K-theory in classifying D-brane charges and analyzes T-duality as a symmetry connecting different theories, including Type ilde{IA} with mixed O-plane configurations.

Findings

T-duality acts as a symmetry between K-theory groups in different string theories.

Identification of stable D-branes in Type ilde{IA} using K-theory and T-duality.

Discovery of brane transfer and charge decay effects due to orientifold planes.

Abstract

Using the relation between D-brane charges and K-theory, we study non-BPS D-branes and their behavior under T-duality. We point out that in general compactifications, D-brane charges are classified by relative K-theory groups. T-duality is found to act as a symmetry between the relative K-theory groups in Type II and Type I/IA theories. We also study Type \tilde\IA theory (which contains an O8^- plane and an O8^+ plane), using K-theory and T-duality to identify its stable D-branes. Comparison with string theory constructions reveals two interesting effects. One of them involves the transfer of branes between O-planes, while in the other, a D-brane charge which seems conserved near one O-plane in fact decays due to the presence of another type of O-plane.