paper

QED with quenched disorder: quantum critical states with interactions and disorder

arXiv:1702.04723 · doi:10.1103/PhysRevB.95.235146

Abstract

Quantum electrodynamics in 2+1-dimensions (QED) is a strongly coupled conformal field theory (CFT) of a U(1) gauge field coupled to two-component massless fermions. The CFT has been proposed as a ground state of the spin-1/2 kagome Heisenberg antiferromagnet. We study QED in the presence of weak quenched disorder in its two spatial directions. When the disorder explicitly breaks the fermion flavor symmetry from SU()U(1)SU() but preserves time-reversal symmetry, we find that the theory flows to a non-trivial fixed line at non-zero disorder with a continuously varying dynamical critical exponent . We determine the zero-temperature flavor (spin) conductivity along the critical line. Our calculations are performed in the large- limit, and the disorder is handled using the replica method.

30 pages + 30 page appendix, 18 figures. Minor changes

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