title: Necessity of Time-Reversal Symmetry Breaking for the Polar Kerr Effect in Linear Response.
abstract: We show that, measured in a backscattering geometry, the polar Kerr effect is absent if the nonlocal electromagnetic response function respects Onsager symmetry, characteristic of thermodynamic states that preserve time-reversal symmetry. A key element is an expression for the reflectivity tensor in terms of the retarded Green's function.
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Weejee
authors.initials: W
authors.lastname: Cho
authors.affiliation: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Kivelson