We investigate and classify Fermi surface behavior for a set of fermionic modes in a family of backgrounds holographically dual to N=4 super-Yang-Mills theory at zero temperature with two distinct chemical potentials. We numerically solve fluctuation equations for every spin-1/2 field in five-dimensional maximally supersymmetric gauged supergravity not mixing with gravitini. Different modes manifest two, one, or zero Fermi surface singularities, all associated with non-Fermi liquids, and we calculate dispersion relations and widths of excitations. We study two limits where the zero-temperature entropy vanishes. In one limit, a Fermi surface approaches a marginal Fermi liquid, which we demonstrate analytically, and conductivity calculations show a hard gap with the current dual to the active gauge field superconducting, while the other is insulating. In the other limit, conductivities reveal a soft gap with the roles of the gauge fields reversed.
|Physical Review D - Particles, Fields, Gravitation and Cosmology
|Published - Nov 6 2012
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)