Hello all,
There will be a special seminar tomorrow (Friday 24 May) at 3 pm in H320. The speaker is N.D. Hari Dass from the Indian Institute for Science; he will be talking about "Varieties of Quantum Measurements." See below for details.
Best,
Dan
Speaker: N.D. Hari Dass (Centre for Quantum Information and Quantum Computation, Indian Institute of Science)
Title: Varieties of Quantum Measurements
Abstract: The first explicit model for quantum measurements was given by von Neumann, strongly influenced by Dirac, for the type of measurements that have come to be known as Projective measurements. In these, the outcomes are always eigenvalues and the post-measurement state is the corresponding eigenstate. This has led to a widespread ’belief’ that quantum measurements always ’irretrievably disturb’ the state of the system. But a number of very interesting measurement schemes have emerged since the von Neumann model, and I shall present these varieties of quantum measurements and critically assess them. That will include i) the Arthurs-Kelly type simultaneous measurements of canonically conjugate observables, ii) the Protective measurements of Aharonov and Vaidman that directly measure expectation values, iii) the weak measurements that do not change the system appreciably at all, and finally iv) the weak value measurements that enable direct measurement of ’normalized’ matrix elements of observables between chosen states. The last kinds are also due to Aharonov and Vaidman.