Bifurcation in Quantum Measurement
Abstract
We present a generic model of (non-destructive) quantum measurement. Being formulated within reversible quantum mechanics, the model illustrates a mechanism of a measurement process --- a transition of the measured system to an eigenstate of the measured observable. The model consists of a two-level system μ interacting with a larger system A, consisting of smaller subsystems. The interaction is modelled as a scattering process. Restricting the states of A to product states leads to a bifurcation process: In the limit of a large system A, the initial states of A that are efficient in leading to a final state are divided into two separated subsets. For each of these subsets, μ ends up in one of the eigenstates of the measured observable. The probabilities obtained in this branching confirm the Born rule.