Speaker: Matt Roberts (University of California-Santa Barbara)
Holographic superconductors, systems of spontaneous U(1) symmetry breaking described via holography through a bulk theory of gravity coupled to electromagnetism and a charged scalar are investigated at zero temperature. Depending on the charge and dimension of the condensate, the infrared theory can have emergent conformal or just Poincare symmetry. In all cases studied, the area of the horizon of the dual black hole goes to zero in the extremal limit, consistent with a nondegenerate ground state. Matt Roberts will also show that there is never a "hard gap''. The real part of the conductivity at low frequency is always nonzero, though it can be exponentially suppressed.