Abstract
A measurement process is logically reversible if the premeasurement density operator of the measured system can be calculated from the postmeasurement density operator and the readout of the measuring apparatus. We show that the continuous-measurement version of a quantum counter, unlike the conventional photon counter, performs a logically reversible measurement. The physical origin for such a distinction is found to be sensitivity to vacuum field fluctuations.
- Received 2 March 1992
DOI:https://doi.org/10.1103/PhysRevLett.68.3424
©1992 American Physical Society
