Monte Carlo Simulation of a Quantum Critical Point in Graphene

Who: Simon Hands (Swansea University)
When: Monday, October 19, 2015 at 14:15
Where: The CP³ meeting room

I review how electrostatic interactions between relativistic electrons moving in a 2d sheet can lead to a Mott insulating phase induced by electron-hole condensation for sufficiently strong coupling, the transition between metallic and insulating phases defining a quantum critical point. Results from numerical simulations of a lattice effective field theory are presented revealing the critical number of species N below which the QCP exists, and its N-dependent characteristics. I next focus on voltage-biased bilayer graphene, for which N=4, which formally resembles QCD with non-zero isospin chemical potential and hence has no Sign Problem. Results for the carrier density, superfluid exciton condensate, and quasiparticle dispersion suggest a Fermi surface at non-zero voltage distorted by strong interactions.