Smeared branes and the Gubser-Mitra conjecture

TL;DR

This paper demonstrates that smeared charged black branes can exhibit dynamical instabilities despite local thermodynamic stability, providing counterexamples to the Gubser-Mitra conjecture.

Contribution

It shows that smeared brane solutions can be dynamically unstable even when thermodynamically stable, challenging the Gubser-Mitra conjecture.

Findings

Smeared branes can have Gregory-Laflamme type instabilities.

Counterexamples to the Gubser-Mitra conjecture are provided.

An ansatz relates charged solutions to neutral ones, aiding the analysis.

Abstract

We show that smeared brane solutions, where a charged black p-brane is smeared uniformly over one of the transverse directions, can have a Gregory-Laflamme type dynamical instability in the smeared direction even when the solution is locally thermodynamically stable. These thus provide counterexamples to the Gubser-Mitra conjecture, which links local dynamical and thermodynamic stability. The existence of a dynamical instability is demonstrated by exploiting an ansatz due to Harmark and Obers, which relates charged solutions to neutral ones.