Measurements, Dynamics and State Preparation in a Micromaser

Günter Manzke, W. Vogel, D.‐G. Welsch

Federico Casagrande, Maria Lisa Garavaglia, ALFREDO LULLI

HERBERT WALTHER

Federico Casagrande, Alessandro Ferraro, ALFREDO LULLI +3 more

We discuss a scheme to relate the phase diffusion dynamics of the micromaser field to the measured atomic population statistics. This can allow us to measure the linewidth of the micromaser spectrum and to solve a relevant decoherence problem in cavity quantum electrodynamics. The main steps are (i) a suitable preparation of the cavity field state to generate coherences, (ii) the transfer of information on the dynamics of field coherences to probe atoms by the action of an external resonant coherent field and (iii) the derivation of the phase diffusion rate, hence the micromaser linewidth, from the measured population statistics of the probe atoms. The method can be applied even in the presence of trapping states, where peculiar linewidth oscillations are expected for increasing pump rate, due to the quantum nature of the micromaser field.

John Jeffers, S. M. Barnett, David Thomas Pegg

We use retrodictive quantum theory to describe cavity field measurements by successive atomic detections in the micromaser. We calculate the state of the micromaser cavity field prior to detection of sequences of atoms in either the excited or ground state, for atoms that are initially prepared in the excited state. This provides the POM elements, which describe such sequences of measurements.

Georg A. Raithel, Oliver J. Benson, HERBERT WALTHER