Quantum State Reduction

Macdonald, Alan

Many writings about quantum measurement posit a universal state reduction: every quantum measurement is accompanied by a state reduction. The supplementary material (next page) provides many examples. However, there are measurements without a state reduction. So authors and teachers should refrain from stating that state reduction is universal.

Masanao Ozawa

Macdonald, Alan

Many writings about quantum measurement posit a universal state reduction: every quantum measurement is accompanied by a state reduction. The supplementary material (next page) provides many examples. However, there are measurements without a state reduction. So authors and teachers should refrain from stating that state reduction is universal.

Garrelt Quandt-Wiese

A phenomenological model for the calculation of reduction probabilities of a superposition of several states is presented, which bases only the idea that quantum state reduction has its origin in a physical interaction between the states. The model is explicitly worked out for the hypothesis of gravity-induced quantum state reduction. It agrees for typical quantum mechanical experiments with the projection postulate and predicts regimes in which other behaviour could be observed. For verification a feasible quantum-optical experiment is proposed. An outlook on the possible role of state reduction for biology is given by exemplarily discussing mutation effects of bacteria.

Masahito Hayashi