Symmetry Restoration and Tachyon Condensation in Open String Theory

TL;DR

This paper explores how D-branes in bosonic string theory can be modeled as noncommutative solitons, demonstrating gauge symmetry restoration and matching soliton tension with D-brane tension, advancing understanding of tachyon condensation.

Contribution

It introduces new solutions showing gauge symmetry restoration to U(∞) outside the soliton core and confirms their tension matches D-brane tension for any noncommutativity parameter.

Findings

Restored U(∞) gauge symmetry outside the soliton core.

Exact agreement of soliton tension with D-brane tension.

Elimination of unwanted modes outside the core.

Abstract

It has recently been argued that D-branes in bosonic string theory can be described as noncommutative solitons, outside whose core the tachyon is condensed to its ground state. We conjecture that, in addition, the local U(1) gauge symmetry is restored to a $U(\infty)$ symmetry in the vacuum outside this core. We present new solutions obeying this boundary condition. The tension of these solitons agrees exactly with the expected D-brane tension for arbitrary noncommutativity parameter $\t$, which effectively becomes a dynamical variable. The restored $U(\infty)$ eliminates unwanted extra modes which might otherwise appear outside the soliton core.