Exactness of the general two-body cluster expansion in many-body quantum theory.
We show that the exact ground-state wave function for an arbitrary two-body Hamiltonian in second-quantized, finite basis set, form cannot generally be represented by a generalized coupled-cluster operator with real finite matrix elements acting on an arbitrary initial trial function.
Davidson
Ernest R
ER
Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27516, USA. erdavid@washington.edu