Physical review letters Condensation of n Bosons and Laser Phase transition Analogy

摘要

A simple analytic expression for the ground state of a dilute gas of N ideal bosons is a 3D harmonic potential at temperature T is derived from the steady state solutions of nonequilibrium equations of motion. The N particle constraint plays the important role of introducing the essential nonlinearity yielding a Ginzburg-Landau free energy. The present analysis has much in common with the quantum theory of the laser, and with the laser phase transition analogy. (S003-9007(99)09008-0)