Abstract

We study the time evolution of the quantum field inside a cavity coupled to a beam of two-level atoms of temperature T, given that each atom, after having crossed the cavity, interacts with a classical field ? and finally with a detector measuring its state. It is shown numerically that, if the atom-quantum field coupling is weak and ? is large, for any given realization of the measurements, any initial state of the cavity field localizes after some time into a squeezed state. The center ? of the squeezed state moves randomly on a line in the complex plane, but the squeezing parameters r and ? show very little fluctuation. Their mean values r? and ?? are independent of the realization, the initial state, and the atom-field coupling constant. The time evolution of r and ? is computed in the limit of weak atom-field coupling and large ?. It is found that r? increases with T;i.e., the squeezing is enhanced by increasing the temperature of the atomic beam. The limitation on the degree of squeezing that can be reached is discussed.