Birth of Closed Strings and Death of Open Strings during Tachyon Condensation

TL;DR

This paper explores the transition from open to closed strings during tachyon condensation, proposing S-branes as a framework to describe time-dependent string dynamics and their interactions.

Contribution

It introduces S-brane actions derived from string worldsheet conformality, providing a new approach to model decaying branes and the emergence of closed strings.

Findings

Open string degrees of freedom decay during tachyon condensation

S-brane actions describe time-dependent string and brane dynamics

Multiple decaying and nucleating closed strings are modeled

Abstract

The tremendous progress achieved through the study of black holes and branes suggests that their time dependent generalizations called Spacelike branes (S-branes) may prove similarly useful. An example of an established approach to S-branes is to include a string boundary interaction and we first summarize evidence for the death of open string degrees of freedom for the homogeneous rolling tachyon on a decaying brane. Then, we review how to extract the flat S-brane worldvolumes describing the homogeneous rolling tachyon and how large deformations correspond to creation of lower dimensional strings and branes. These S-brane worldvolumes are governed by S-brane actions which are on equal footing to D-brane actions, since they are derived by imposing conformality on the string worldsheet, as well as by analyzing fluctuations of time dependent tachyon configurations. As further examples we generalize previous solutions of the S-brane actions so as to describe multiple decaying and nucleating closed fundamental strings. Conceptually S-brane actions are therefore different from D-brane actions and can provide a description of time dependent strings/branes and possibly their interactions.