Quantum mechanical heat transport in disordered harmonic chains.

We investigate the mechanism of heat conduction in ordered and disordered harmonic one-dimensional chains within the quantum mechanical Langevin method. In the case of disordered chains we find indications for normal heat conduction, which means that there is a finite temperature gradient, but we cannot clearly decide whether the heat resistance increases linearly with the chain length. Furthermore, we observe characteristic quantum mechanical features like the Bose-Einstein statistics of the occupation numbers of the normal modes, freezing of the heat conductivity, and influence of the entanglement within the chain on the current. For the ordered chain we recover some classical results like a vanishing temperature gradient and a heat flux independent of the length of the chain.