Quantum Information, Irreversibility and State Collapse in Some Microscopic Models of Measurement

Abstract

The quantum measurement problem considered for measuring system (MS) model which consist of measured state S (particle), detector D and information processing device O. For spin chains and other O models the state evolution for MS observables measurements studied. It's shown that specific O states structure forbids the measurement of MS interference terms which discriminate pure and mixed S states. It results in the reduction MS Hilbert space to O representation in which MS evolution is irreversible, which in operational formalism corresponds to S state collapse. In radiation decoherence O model Glauber restrictions on QED field observables results in analogous irreversible MS + field evolution. The results interpretation in Quantum Information framework and Rovelli Relational Quantum Mechanics discussed.