On non-uniform black branes
Steven S. Gubser
TL;DR
This work analyzes the non-uniform endpoints of the Gregory-Laflamme instability for uncharged black strings in five dimensions using a perturbative expansion around the uniform solution. It constructs static non-uniform branches and computes their thermodynamic properties, finding that the leading-order change in the critical parameter $\eta$ is positive ($\eta_1 \approx 1.45$) while the higher-order entropy difference is negative ($\sigma_2 \approx -0.59$), signaling a first-order transition. The results imply that non-uniform endpoints exist at finite non-uniformity and that the transition from uniform to non-uniform branes is not smooth, with broader implications for other brane systems and their phase structure. The study also discusses methodological challenges, numerical refinements, and future directions for higher-order perturbative analyses and real-time dynamics.
Abstract
Certain black branes are unstable toward fluctuations that lead to non-uniform mass distributions. We study static, non-uniform solutions that differ only perturbatively from uniform ones. For uncharged black strings in five dimensions, we find evidence of a first order transition from uniform to non-uniform solutions.
