Department of Physics & Astronomy
University of New Mexico

CQuIC Seminars

How to count one photon and get a result of 1000 -- and other experiments on quantum measurement

Presented by Aephraim Steinberg, University of Toronto

I will present experiments studying the results of quantum measurements carried out on post-selected systems.

In 1988, Aharonov, Albert, and Vaidman introduced a new paradigm of quantum measurement in a paper which had the unwieldy but provocative title "How the result of a measurement of a component of the spin of a spin-1/2 particle can turn out to be 100."

However, nearly all of the experiments carried out so far on their so-called "weak measurements" could be alternatively understood in terms of the classical (electromagnetic wave) theory of optics. I will present the first experiment in which a measurement apparatus deterministically entangles two distinct optical beams, enabling us to experimentally address a question directly analogous to that of the original proposal:

"In a two-arm interferometer containing one photon in total, can the result of a measurement of the photon number in one arm turn out to be greater than 1"

The answer proves to be yes.

3:30 pm, Thursday, April 11, 2019
PAIS-2540, PAIS

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A schedule of talks within the Department of Physics and Astronomy is available on the P&A web site at http://physics.unm.edu/pandaweb/events/index.php