Noisy Branes

Brane intersections are the prototypical example of string theory realizations of gauge theories with fundamental matter. We employ the D3/D5 brane intersection to study the effects of disorder on strongly coupled compressible matter in 2+1 dimensions. We consider the system at finite temperature in the presence of a disordered chemical potential, and first study the effects of disorder on the charge density and the quark condensate. Next, we focus on the DC conductivity and derive analytic expressions for the corrections induced by weak disorder. We present numerical simulations both for weak and moderate disorder, and show how strong enough disorder induces a sub-linear behavior for the conductivity as a function of the charge density. This behavior qualitatively agrees with that of the DC conductivity of semi-metal graphene in the proximity of the charge neutrality point.