Origin of dissipative dynamics in correlated few electron systems

Graphical abstract: Unidirectional dynamics in the valence electron system of sodium clusters of different sizes. - Abstract: We investigate the origin of the quasi-unidirectional behaviour of the entropy of the valence electrons of Nan clusters with n=2-8. The multi-electron wave function is propagated using the explicitly time-dependent configuration interaction approach, from which the dynamics of the reduced density operator can be calculated accurately. The entropy, as calculated from the reduced density operator, depends on the populations of the natural orbitals, for which a markedly different time dependence is found, compared to the populations of the Hartree-Fock orbitals.