Diffusion Constant of a Quantum Particle Moving in Tight-Binding Media Modulated by Non-White Noises

概要

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Diffusion of a particle or an excitation in randomly fluctuating media is studiedtheoretically. The model is a tight-binding Hamiltonian whose diagonal or off-diagonal elements are modulated by mutually-independent random noises. Thenon-white modulation models are investigated precisely. The diffusion constant(7)) depends on the noise-parameters such as the amplitude (J) and the cor-relation time (7 ') and also depends on the static band width ( W). Explicitcalculation of D has been performed by using the dynamical coherent potentialapproximation and by computer experiments. In the case thxt diagonal elementsare modulated by discrete-jump noises, D as a function of y has a minimum inthe vicinity of 1y=A if J>>W. On the contrary, Day) is a monotonically-increasingfunction of 7 if UK< W. In the off-diagonal fluctuation case, the diffusion constantexhibits a feature qualitatively different from the diagonal fluctuation model.
社団法人日本物理学会の論文
1983-09-15