A Note on D-Branes of Odd Codimensions from Noncommutative Tachyons

TL;DR

This paper constructs explicit codimension-one solitons in noncommutative space, identifies them with D-branes, computes their tensions exactly, and explores their relation via T-duality, revealing gauge symmetry aspects and implications for non-BPS D-branes.

Contribution

It explicitly constructs a codimension-one noncommutative soliton as a D-brane and demonstrates its tension matches theoretical expectations, clarifying T-duality as a gauge symmetry.

Findings

Explicit construction of a noncommutative D24-brane

Exact tension calculation confirming T-duality relations

Proposal of new descent relations for non-BPS D-branes

Abstract

On a noncommutative space of rank-1, we construct a codimension-one soliton explicitly and, in the context of noncommutative bosonic open string field theory, identify it with the D24-brane. We compute the tension of the proposed D24-brane, yielding an exact value and show that it is related to the tension of the codimension two D23-brane by the string T-duality. This resolves an apparent puzzle posed by the result of Harvey, Kraus, Larsen and Martinec and proves that the T-duality is a gauge symmetry; in particular, at strong noncommutativity, it is part of the U(oo) gauge symmetry on the worldvolume. We also apply the result to non-BPS D-branes in superstring theories and argue that the codimension-one soliton gives rise to new descent relation among the non-BPS D-branes in Type IIA and Type IIB string theories via T-duality.