Thermoelectric transport near pair breaking quantum phase transition out of d-wave superconductivity

We study electric, thermal, and thermoelectric conductivities in the vicinity of a z=2 superconductor-diffusive metal transition in two dimensions, both in the high and low frequency limits. We find violation of the Wiedemann-Franz law and a dc thermoelectric conductivity $\alpha$ that does not vanish at low temperatures, in contrast to Fermi liquids. We introduce a Langevin equation formalism to study critical dynamics over a broad region surrounding the quantum critical point.