Disorder correction to equilibrium in a perfect electric wire

Quantum coherence properties are attractive for making a quantum computer, but they are easily destroyed by environmental disorder. This contribution examines a way of achieving a perfect electric wire of gallium arsenide such that charge carriers move unscattered despite the environmental disorder due to the unavoidable thermal agitation. The example is academic yet experimental. Carrier motion through the crystal is theoretically investigated within a fully quantum framework, simpler than decoherence theory, where the occupancy of classical states is replaced by a Wigner function. The effect of a weak disorder is accounted for analytically by means of a multiple-scale method without a Markov assumption. Even though carriers do move ballistically over several micrometres, the thermal disorder gives rise to important fluctuations about the thermodynamic equilibrium state at temperatures above 0.05 K.