Entanglement, joint measurement, and state reduction (Q1410193)

In the paper under review the joint measurement formula (JMF) in quantum measurement theory is investigated. It is shown that JMF is equivalent to the fact that nonselective measurement of one member of a pair of entangled noninteracting systems has no effect on measurement probabilities for the other member (NOEFFECT) in conjunction with a product formula for joint probabilities. It is show that for general observables NOEFFECT does not imply JMF. The state reduction formula is shown to be a corollary of JMF.