Abstract
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
- www.qubit.it - Website of QUIT group
- http://arxiv.org/pdf/quant-ph/0310041 - There exist non orthogonal quantum measurements that are perfectly repeatable