Abstract:
I will start with a quick review of the simple equation derived in 1963 to calculate the ground state energy E of a dilute Bose gas with 2-body repulsive interactions. It yielded the famous LHY second order term for E. Beyond that it has been recently been shown to agree remarkably well with Monte Carlo calculations in 3 dimensions for ALL densities, revealing what might be previously unsuspected changes at intermediate density.