Work required for selective quantum measurement. (8th June 2018)

• Record Type: Journal Article
• Authors: Konishi, Eiji
• Is Part Of: Journal of statistical mechanics. (2018:Jun.)
• Publication Date: 2018-06-08
• Subjects: 9 -- 2; Statistical mechanics -- Periodicals; Mechanics -- Statistical methods -- Periodicals; 530.1305
• DOI: 10.1088/1742-5468/aac13f
• Languages: English
• ISSNs: 1742-5468

Abstract

Abstract: In quantum mechanics, we define the measuring system M in a selective measurement by two conditions. Firstly, when we define the measured system S as the system in which the non-selective measurement part acts, M is independent from the measured system S as a quantum system in the sense that any time-dependent process in the total system S + M is divisible into parts for S and M . Secondly, when we can separate S and M from each other without changing the unitary equivalence class of the state of S from that obtained by the partial trace of M, the eigenstate selection in the selective measurement cannot be realized. In order for such a system M to exist, we show that in one selective measurement of an observable of a quantum system S 0 of particles in S, there exists a negative entropy transfer from M to S that can be directly transformed into an amount of Helmholtz free energy of where T is the thermodynamic temperature of the system S . Equivalently, an extra amount of work, , is required to be done by the system M .