Like the laser, the micromaser is a highly interesting physical system which relies on the atomic process of stimulated emission, described by Einstein over eight decades ago. Specifically, atoms passing through the chamber of the micromaser interact with only a single mode of the electromagnetic field of the cavity.

In recent years Prof. W. C. Schieve has carried out leading research into the understanding of the statistical properties of the micromaser. Specifically, he and Dr. Rebecca McGowan have studied the statistical evolution of the phase of the atomic state, as indicated by matrix elements of the density operator.

In the case of a steady-state of the micromaser, the phase evolution is governed by a Fokker-Planck equation. But in the case where the cavity is pumped by injection of certain phase elements, the evolution of density operator is much more complicated, and more interesting.

In recent articles in the Physical Review, Dr. Schieve and Dr. McGowan showed that exact and approximate solutions are available in this case.