  Monte Carlo simulation of a 2+1 dimensional model of voltage-biased bilayer
graphene, consisting of relativistic fermions with chemical potential mu
coupled to charged excitations with opposite sign on each layer, has exposed
non-canonical scaling of bulk observables near a quantum critical point found
at strong coupling. We present a calculation of the quasiparticle dispersion
relation E(k) as a function of exciton source j in the same system, employing
partially twisted boundary conditions to boost the number of available momentum
modes. The Fermi momentum k_F and superfluid gap Delta are extracted in the
limit j tends to zero for three different values of mu, and support a strongly
interacting scenario at the Fermi surface with Delta of order O(mu). We propose
an explanation for the observation mu < k_F in terms of a dynamical critical
exponent z < 1.
