Regular versus chaotic dynamics in closed systems of interacting Fermi particles

摘要

We discuss dynamical properties of strongly interacting Fermi-particles. Main attention is paid to the evolution of wave packets in the many-particle basis of non-interacting particles. Specifically, we analyze the time dependence of the return probability and the Shannon entropy of packets. We start with the model of two-body random interaction which allows us to obtain analytical expression for the time dependence of the above quantities. Analytical results are compared with numerical data obtained in direct simulation of the wave packet dynamics. To understand to what extent these results are generic, we have considered the spin model of a quantum computation with a non-random (dynamical) interaction between spins. We have found that the linear increase of the Shannon entropy observed in the two-body random model, occurs, under some conditions, in the dynamical model. Finally, we have analyzed the role of weak external perturbation taken in the form of static disorder.