Designer bubble walls in a holographic Weyl semi-metal with magnetic field

Abstract

We study bubble walls in the holographic D3/probe D7 system that is dual to strongly coupled quark dynamics. We work to construct holographic descriptions of bubble wall junctions where we can tune the bubble wall height and pressure difference in a theory at zero temperature and density. We study the system in the presence of a background axial vector field b (associated with the z direction) that induces a Weyl semi-metal, massless phase and a perpendicular background magnetic field Bx which favours mass generation. We find a first order transition line in the mass-Bx plane, at fixed b, ending at a critical point. We present some preliminary solutions of PDEs that describe the motion of one dimensional bubble walls in this theory, with a stationary initial condition - large pressure differences accelerate the wall to the speed of light whilst when the pressure difference is small the wall slumps to an interpolating solution. We also take the first steps to include temperature and see evidence of thermal drag slowing the wall motion. Slump configurations at finite temperature show some signs of a back pressure wave against the wall motion.