Quantum Mechanical Heat Transport in Disordered Harmonic Chains

We investigate the mechanism of heat conduction in ordered and disordered harmonic onedimensional chains within the quantum mechanical Langevin method. In the case of the 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 Bose-Einstein statistics of the occupation numbers of the normal modes, freezing of the heat conductivity and the 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.