Organizers:
David Dean
Rodney Bartlett
Walter Johnson
Achim Schwenk
Program Coordinator: Application form Symposium on "50 Years of Coupled Cluster Theory" Exit report

June 23  July 25, 2008
A systematic implementation of coupledcluster theory for nuclei is underway. This effort utilizes the formalism of coupledcluster developments in chemistry, but with both physical and computational twists inherent in the physics of nuclei. The nuclear problem requires as input an interaction that is less well understood than in the atomic and chemical cases and a close interaction between those who produce realistic nucleonnucleon interactions and the manybody specialists is required. In light nuclear systems, some significant tests of interactions have been made with configurationinteraction and quantum Monte Carlo calculations. It would appear that a real threebody interaction is required to reliably predict nuclear properties. The introduction of threebody interactions into the coupledcluster formalism constitutes one interesting discussion point for this program. A second point from nuclear physics involves efforts to utilize a singleparticle basis that includes bound, continuum, and scattering states. The coupledcluster problem then translates to a complex algorithm for weakly bound nuclei. Recent significant advances in developing coupledcluster theory have occurred in quantum chemistry. A variety of coupledcluster methods for ground, excited, closedshell, and openshell, nondegenerate and quasidegenerate states of atoms and molecules and molecular properties have been developed and coded, so that nowadays coupledcluster methods are regarded by theoretical and experimental chemists as the best ab initio techniques for highaccuracy electronic structure calculations. In atomic physics, Parity Nonconservation (PNC) effects are one interesting focus where a relativistic coupledcluster method will play a key role. Various atomic isotope shifts and applications in fundamental symmetries are also being pursued. Other important developments include the proper CC treatment of QED effects. The goals of this program are as follows:
