QUANTUM-MONTE-CARLO CALCULATIONS FOR BOSONS IN A 2-DIMENSIONAL HARMONIC TRAP

Path-Integral-Monte-Carlo simulation has been used to calculate the pr operties of a two-dimensional (2D) interacting Bose system. The bosons interact with hard-core potentials and are confined to a harmonic tra p. Results for the density profiles, the condensate fraction, and the superfluid density are presented. By comparing with the ideal gas we e asily observe the effects of finite size and the depletion of the cond ensate because of interactions. The system is known to have no phase t ransition to a Bose-Einstein condensation in 2D, but the finite system shows that a significant fraction of the particles are in the lowest state at low temperatures.