Theory Seminar

An optimal no-go theorem on hidden variable theories

Yuri Gurevich

Microsoft Research
Friday, October 06, 2017
10:30am - 11:30am
BBB 3725

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The room information was previously incorrectly listed as EECS 3725. It is now correct.

About the Event

Hidden-variable theories allege that a state of a quantum system, even if the state is pure and thus contains as much information as quantum mechanics permits, actually describes an ensemble of systems with distinct values of some hidden variables. Once the values of these variables are specified, the system becomes determinate or at least more determinate than quantum mechanics says. Thus the randomness in quantum predictions results, entirely or partially, from the randomness involved in selecting a member of the ensemble.

No-go theorems assert that, under reasonable assumptions, hidden-variable theories cannot reproduce the predictions of quantum mechanics. Classical no-go theorems of 1960s establish the unpredictability of the values of quantum measurements. Some recent no-go theorems assert the unpredictability of the expectation values of quantum measurements. We will present such an expectation no-go theorem. It implies all the previous expectation no-go theorems, and it is optimal in the sense that the natural weakenings of the assumptions and the natural strengthenings of the conclusion fail.

The lecture is based on the joint work with Andreas Blass. We will not presume the knowledge of quantum mechanics.

Additional Information

Contact: Grant Schoenebeck

Sponsor(s): CSE

Open to: Public