Tachyon Effective Actions In Open String Theory

TL;DR

This paper demonstrates how the Dirac-Born-Infeld action coupled with a tachyon can be derived from open string theory in a specific limit, clarifying its relation to full string dynamics.

Contribution

It generalizes the limit used to derive the DBI action, providing a deeper understanding of the tachyon's role in open string theory.

Findings

The DBI action with tachyon can be obtained from open string theory in a specific limit.

This limit extends previous derivations of the DBI action.

The work clarifies the aspects of open string theory captured by the tachyonic DBI action.

Abstract

We argue that the Dirac-Born-Infeld (DBI) action coupled to a tachyon, that is known to reproduce some aspects of open string dynamics, can be obtained from open string theory in a certain limit, which generalizes the limit leading to the usual DBI action. This helps clarify which aspects of the full open string theory are captured by this action.