Date Published:

NOV 15

Abstract:

We discuss a generalized dynamic mean-field method combining the advantages of explicit pair correlations and of configuration interaction. The approximate dynamical method, which we call time-dependent self-consistent-field configuration interaction (TDSCF2-CI), is constructed by including N(N-1)/2 TDSCF2 configurations. In each configuration a given pair of N coupled modes is directly (not in the mean-field approach) correlated; the N(N-1)/2 configurations include all such choices of pairs. As such, it has both the usual advantages of TDSCF and improvements due to some inclusion of correlations (exact results for any two-mode problem, improved descriptions of dynamical corrections, and greater accuracy). A three-mode model Hamiltonian is analyzed using five approximate treatments, i.e., the usual TDSCF, the three TDSCF2 forms, and the TDSCF2-CI one. The quantities for comparison with the exact results include the decay P(t) of the initial state, the time dependencies of the energies e (i) of individual modes, and the overlap S (t) of the corresponding approximate wave function with the exact one. We find, indeed, that explicit inclusion of pair correlations improves the description of the quantum dynamics of the system.