



01300nas a2200145   4500008004100000245008500041210006900126260001300195490000800208520083900216100002101055700002501076700001601101856003701117       2019                        eng d00aFluctuation-induced torque on a topological insulator out of thermal equilibrium0 aFluctuationinduced torque on a topological insulator out of ther  c8/1/20190 v1233 a<p>Topological insulators with the time reversal symmetry broken exhibit strong magnetoelectric and magneto-optic effects. While these effects are well-understood in or near equilibrium, nonequilibrium physics is richer yet less explored. We consider a topological insulator thin film, weakly coupled to a ferromagnet, out of thermal equilibrium with a cold environment (quantum electrodynamics vacuum). We show that the heat flow to the environment is strongly circularly polarized, thus carrying away angular momentum and exerting a purely fluctuation-driven torque on the topological insulator film. Utilizing the Keldysh framework, we investigate the universal nonequilibrium response of the TI to the temperature difference with the environment. Finally, we argue that experimental observation of this effect is within reach.</p>1 aMaghrebi, M., F.1 aGorshkov, Alexey, V.1 aSau, J., D.  uhttps://arxiv.org/abs/1811.06080