LOGICAL REVERSIBILITY IN QUANTUM MEASUREMENT - GENERAL-THEORY AND SPECIFIC EXAMPLES

Citation
M. Ueda et al., LOGICAL REVERSIBILITY IN QUANTUM MEASUREMENT - GENERAL-THEORY AND SPECIFIC EXAMPLES, Physical review. A, 53(6), 1996, pp. 3808-3817
Citations number
22
Categorie Soggetti
Physics
Journal title
ISSN journal
10502947
Volume
53
Issue
6
Year of publication
1996
Pages
3808 - 3817
Database
ISI
SICI code
1050-2947(1996)53:6<3808:LRIQM->2.0.ZU;2-5
Abstract
A measurement process is logically reversible if the premeasurement de nsity operator of the measured system is uniquely determined from the postmeasurement density operator and the outcome of the measurement. T his paper analyzes the necessary and sufficient condition for a measur ement process to be logically reversible and discusses specific exampl es on quantum-nondemolition measurements. quantum counting, and measur ement of spin systems. It is shown that for any sharp measurement we c an construct a logically reversible measurement that continuously appr oaches the sharp measurement with a decrease in the measurement error. A general condition for a measurement process to be reversed by anoth er with a nonzero probability of success is given, and the implication s of such physical reversibility are discussed.