Onset of nonequilibrium in a driven Anderson insulator

The onset of nonequilibrium in a driven Anderson-insulator is identified by monitoring the system with two-thermometers. Features of nonequilibrium appear at surprisingly weak drive intensity demonstrating, among other things, that conductivity may not be a reliable thermometer for ensuring linear-response conditions. In addition, the spectral contents of the applied field could be more important to take the system out of equilibrium than its absorbed power. Ensuing hot-electron transport effects and the nontrivial role phonons play in driven quantum systems are pointed out.