The field of the one-atom maser, or micromaser, shows strong variations in certain parameter regions usually identified as phase transitions. In this paper the time development of the field in the vicinity of those regions is investigated. Depending on the parameters, spontaneous jumps or slow transitions between two metastable field values can be observed. Hystersis behavior also occurs. The results are explained by means of a quantum Monte Carlo simulation of the maser field as well as a Fokker-Planck description used earlier in micromaser theory.

• Received 24 January 1994

DOI:https://doi.org/10.1103/PhysRevLett.72.3506