Brane-Antibrane Systems at Finite Temperature and the Entropy of Black Branes

TL;DR

The authors propose a finite-temperature brane-antibrane framework in which open-string degrees of freedom reappear from the closed-string vacuum and can stabilize at high temperature, enabling a microscopic description of non-extremal black branes. Using decoupled brane and antibrane gas sectors and AdS/CFT guidance, they reproduce the neutral black three-brane entropy and extend the construction to M2- and M5-branes, obtaining correct scaling but a universal factor-of-2^{p/(p+1)} mismatch relative to supergravity. The model explains negative specific heat and pressure via brane-antibrane annihilation and captures dynamical instabilities such as the Gregory-Laflamme transition, including the formation of black holes and lower-dimensional branes, with extensions to eleven dimensions. While offering compelling qualitative and quantitative insights, the work also highlights unresolved issues, including the precise energy-density matching between the two gases and the role of the Hagedorn transition in this brane-antibrane context.

Abstract

We consider D-brane/anti-D-brane systems at T>0. Starting at the closed string vacuum, we argue that a finite temperature leads to the reappearance of open string degrees of freedom. We also show that, at a sufficiently large temperature, the open string vacuum becomes stable. Building upon this observation and previous work by Horowitz, Maldacena and Strominger, we formulate a microscopic brane-antibrane model for the non-extremal black three-brane in ten dimensions (as well as for the black two- and five-branes in eleven dimensions). Under reasonable assumptions, and using known results from the AdS/CFT correspondence, the microscopic entropy agrees with the supergravity result up to a factor of 2^(p/p+1), with p the dimension of the brane. The negative specific heat and pressure of the black brane have a simple interpretation in terms of brane-antibrane annihilation. We also find in the model states resembling black holes and other lower-dimensional black branes.

Figures (2)

• Figure 1: Tachyon potential for the brane-antibrane system. The physical range for the field is $|\phi|<\sqrt{\pi/2}$ ($0\leq |t|<\infty$); the dotted lines outside this range have been drawn to aid the eye.
• Figure 2: Mass of the open string tachyon in string units as a function of the inverse temperature, for $g_s N=10^{-10}$ (solid line) and $g_s N=1$ (dashed line), where $N$ is the number of D9-$\overline{\hbox{D9}}$ pairs. The vertical line indicates the Hagedorn temperature, $\beta_{H}=2\sqrt{2}\pi$. See text for discussion.