Neoclassical radiation theory as an integral part of the Monte Carlo wave-function method

Abstract

We analyze the so-called Monte Carlo wave-function (MCWF) method from a conceptual point of view. This method has been recently introduced as a technique to simulate dissipative processes in quantum optics. For the case where dissipation consists of spontaneous emission, we find that the coherent decay part of the MCWF method is identical to neoclassical radiation theory. This unexpected reappearance of the neoclassical theory suggests the identification of the MCWF coherent decay with classical radiation reaction. It leads to an alternative interpretation of the MCWF method instead of the usual one which is based upon quantum measurmeent theory. We give a derivation of the MCWF method, illustrated by simple Feynman diagrams, in which the appearance of radiation reaction is shown to be a natural feature of the coherent decay part.