Determination of dynamical exponents of graphene at quantum critical point by holography

Abstract

We calculate the transport of a theory with two conserved currents by the holographic method and compare it with graphene data to determine its dynamical exponents (z, theta), which characterizes a "quantum critical point." As a result, we find that the electric and the thermal conductivity data can be fit more naturally if we assume (z, theta) = (3/2,1) rather than (1,0). Furthermore, we find that thermoelectric power data at high temperature can be fit if we use (3/2,1) but not by (1,0). The theta = 1 result can be interpreted as taking into account the fermionic nature of the electrons, and z = 3/2 can be interpreted as the flattened band by the strong interaction.