Quantum Measurement

• Luders change-of-state formula in ideal measurement rederived from the concept of minimal measurement. Equivalence of ideal and predictive measurement preserving sharp values of compatible observables.
• The mixing character of a quantum state is strictly increasing in incomplete measurement. This points out the mixing character as as a refinement of the notion of entropy, yielding the factorization of the realistic quantum processes onto evolution and collapse.
• A detailed study of Jauch's approach to the quantum theory of measurement was performed.
• Retroactive apparent occurrence (RAO) of events in quantum mechanics is precisely defined. It enables to include the old intuitive idea of Niels Bohr ("Only a registered phenomenon is truly a phenomenon") into modern quantum theory of measurement. Also, RAO explaines the known delayed-choice experiments due to John Wheeler.
• Classification of quantum measurements.
• Evolution of the system during the continuous ideal measurement of an observable is described by the modified hamiltonian. Freezing of state (Zeno's paradox) is studied.