THE OPEN XY MODEL

Abstract

Using the weak coupling limit as a quantum functional central limit (in the sense of Accardi, Frigerio and Lu), we give a quantum Markovian description of the open XY-model, followed by the large-N limit. The treatment is noteworthy for the fact that the harmonic decomposition of the stochastic dynamics is not that of the free evolution, but rather arises from the macroscopic variables being studied. We conclude with a simple Hilbert module formulation of the dynamics.