The Problem of Measurement and the Theory of Quantum State Reduction

Abstract

A new approach to the problem of measurement in quantum mechanics is proposed. In this approach, the process of measurement is described in the Heisenberg picture and divided into two stages. The first stage is to transduce the measured observable to the probe observable. The second stage is to amplify the probe observable to the macroscopic meter observable. Quantum state reduction is derived, based on the quantum Bayes principle, from the object-apparatus interaction in the first stage. The dynamical process of the second stage is described as a quantum amplification with infinite gain based on nonstandard analysis.