SIMULTANEOUS MEASUREMENT OF CONJUGATE VARIABLES

This paper investigates the possibility to extract optimum information about the momentum and position variables of a quantum mechanical system. For the observation we use a pair of independent detectors, which contribute their own noise to the recorded result. In the optimal case the setup measures the Q-distribution leading to antinormally ordered expectation values. The class of initial detector states to be used is discussed, and the relation to measurement theory is elucidated. The paper summarizes and unifies earlier works by Husimi, Arthurs, and Kelly and Braunstein, Caves and Milburn. A realization in quantum optics is suggested. © 1992.