An Isaac Newton Institute Workshop

Quantum Statistics - quantum measurements, estimation and related topics

Repeatable measurements without eigenstates

Authors: F. Buscemi (QUIT group, Universita' di Pavia), G. M. D'Ariano (QUIT group, Universita' di Pavia), P. Perinotti (QUIT group, Universita' di Pavia)


We show that, contrarily to the widespread belief, in quantum mechanics repeatable measurements are not necessarily described by orthogonal projectors-the customary paradigm of observable. Nonorthogonal repeatability, however, occurs only for infinite dimensions. We also show that when a non orthogonal repeatable measurement is performed, the measured system retains some "memory" of the number of times that the measurement has been performed.

Related Links