title: Exactness of two-body cluster expansions in many-body quantum theory.
abstract: The Horn-Weinstein formula and the variational principle, combined with numerical results for a few many-electron systems, are used to provide support for a conjecture that the exact ground-state wave function for a Hamiltonian system containing up to two-body terms may be represented by an exponential cluster expansion employing a finite two-body operator.
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA. piecuch@cem.msu.edu
authors.forename: Piotr
authors.initials: P
authors.lastname: Piecuch
authors.forename: Karol
authors.initials: K
authors.lastname: Kowalski
authors.forename: Peng-Dong
authors.initials: PD
authors.lastname: Fan
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Jedziniak