Finite Temperature Systems of Brane-Antibrane Pairs and Non-BPS D-branes

TL;DR

This paper explores the thermodynamic behavior of brane-antibrane pairs and non-BPS D-branes at finite temperature, revealing phase transitions near the Hagedorn temperature and conditions for their stability and creation.

Contribution

It provides the first detailed calculation of the finite temperature effective potential for these branes in various backgrounds, showing phase transitions and stability criteria.

Findings

Phase transition occurs slightly below the Hagedorn temperature.

Large N D9-anti-D9 pairs become stable near the Hagedorn temperature.

Open strings dominate the total energy in thermodynamic balance.

Abstract

We investigate the thermodynamic properties of D-brane-anti-D-brane pairs and non-BPS D-branes on the basis of boundary string field theory. We calculate the finite temperature effective potential of N D-brane-anti-D-brane pairs in a non-compact background and in a toroidal background. In the non-compact background case, a phase transition occurs slightly below the Hagedorn temperature, and the D9-anti-D9 pairs become stable. Moreover, the total energy at the critical temperature is a decreasing function of N as long as the 't Hooft coupling is very small. This leads to the conclusion that a large number N of D9-anti-D9 pairs are created simultaneously near the Hagedorn temperature. In the toroidal background case (M_{1,9-D} * T_{D}), a phase transition occurs only if the Dp-anti-Dp pair is extended in all the non-compact directions, as long as the 't Hooft coupling is very small. The total energy at the critical temperature also decreases as N increases. We also calculate the finite temperature effective potential of non-BPS D-branes, and we obtain similar results. Then, we consider the thermodynamic balance between open strings on these branes and closed strings in the bulk in the ideal gas approximation, and conclude that the total energy is dominated by the open strings.