Striped phases of N=4 SYM at finite density

Abstract

We construct spatially modulated phases of strongly coupled $\mathcal N=4$ supersymmetric Yang--Mills theory at finite $R$-charge density. Compactification on a three-torus and unequal background charges isolate an unstable charge-density mode. Its static threshold seeds a nonlinear branch of striped black branes in the STU model. The striped states have higher entropy than homogeneous states with the same energy and conserved charges. They connect continuously to the homogeneous branch, with an entropy excess that begins at fourth order in the modulation amplitude. These solutions provide a candidate endpoint of the charge-transport instability.