caa a22 4500 465801064 CHVBK 20180323112052.0 cr unu---uuuuu 170327e19900601xx s 000 0 eng 10.1007/BF01290618 doi (NATIONALLICENCE)springer-10.1007/BF01290618 Mean field approximation versus exact treatment of collisions in few-body systems [Elektronische Daten] [J. Lemm, A. Weiguny, B. Giraud] A variational principle for calculating matrix elements of the full resolvent operator for a many-body system is studied. Its mean field approximation results in nonlinear equations of Hartree (-Fock) type, with initial and final channel wave functions as driving terms. The mean field equations will in general have many solutions whereas the exact problem being linear, has a unique solution. In a schematic model with separable forces the mean field equations are analytically soluble, and for the exact problem the resulting integral equations are solved numerically. Comparing exact and mean field results over a wide range of system parameters, the mean field approach proves to be a very reliable approximation, which is not plagued by the notorious problem of defining asymptotic channels in the time-dependent mean field method. Springer-Verlag, 1990 24.10.−i nationallicence 25.10.+s nationallicence 24.90.+d nationallicence Lemm J. Institut für Theoretische Physik, Universität Münster, Federal Republic of Germany aut Weiguny A. Institut für Theoretische Physik, Universität Münster, Federal Republic of Germany aut Giraud B. Service de Physique Théorique, CEN Saclay, Gif-sur-Yvette, France aut Zeitschrift für Physik A Atomic Nuclei Springer-Verlag 336/2(1990-06-01), 179-188 0939-7922 336:2<179 1990 336 218 https://doi.org/10.1007/BF01290618 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01290618 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lemm J. Institut für Theoretische Physik, Universität Münster, Federal Republic of Germany aut NATIONALLICENCE 700 1- Weiguny A. Institut für Theoretische Physik, Universität Münster, Federal Republic of Germany aut NATIONALLICENCE 700 1- Giraud B. Service de Physique Théorique, CEN Saclay, Gif-sur-Yvette, France aut NATIONALLICENCE 773 0- Zeitschrift für Physik A Atomic Nuclei Springer-Verlag 336/2(1990-06-01), 179-188 0939-7922 336:2<179 1990 336 218 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer