OPTIMIZED LOWER-BOUND FOR 4-BODY HAMILTONIANS

Generalizing a method elaborated for three-body systems, we derive a n ew lower bound on four-body ground-state energies in terms of two-body binding energies in the unequal-mass case. For simple power-law poten tials, this bound is compared to variational calculations and is shown to be very close to the exact result. In particular, it gives the exa ct answer for harmonic interactions.