Trimer binding in two dimensions

Abstract
The ground state energies of loosely bound boson and fermion trimers interacting via Lennard-Jones (12,6) pair potentials in two dimensions are evaluated with variational calculations. Threshold coupling constants for self-binding are determined by extrapolation to zero binding energy. The results are used to give estimates of the binding energy of the 4He trimer and in a discussion of the ordering of dimer and trimer thresholds in two dimensions.