Decay of currents for strong interactions.

摘要: The decay of current autocorrelation functions is investigated for quantum systems featuring strong interactions. Here the term "interaction" refers to that part Hamiltonian causing (major) current. On time scale before (first) zero crossing current, its relaxation shown be well described by a suitable perturbation theory in lowest orders interaction strength, particularly if interactions are strong. In this description found rather close Gaussian and resulting diffusion coefficient approximately scales with inverse strength. These findings confirmed numerical results from exact diagonalization several one-dimensional transport models including spin Heisenberg chain respect different numbers, anisotropy, next-nearest-neighbor interaction, or alternating magnetic field; energy Ising tilted excitations randomly coupled modular system. impact these weak discussed.