Physics and Astronomy Colloquium
Taming God's dice
Presented by Dr. Krister Shalm (NIST)
In 1943 Einstein wrote to Max Born saying “As I have said so many times, God doesn't play dice with the world.” This discussion with Born was just one part of a much large debate on the consequences of quantum theory on the nature of reality. In 1935 Einstein, Podolsky, and Rosen famously published a paper with the aim of showing that the wave function in quantum mechanics does not provide a complete description of reality. The gedanken experiment showed that quantum theory, as interpreted by Niels Bohr, leads to situations where distant particles, each with their own “elements of reality,” could instantaneously affect one another. Such action at a distance seemingly conflicts with relativity. The hope was that a local theory of quantum mechanics could be developed where individual particles are governed by elements of reality, even if these elements are hidden from us. In such a theory, now known as local realism, these elements of reality or hidden variables could remove the randomness inherent in quantum mechanics.
In 1964 John Bell in a startling result showed that the predictions of quantum mechanics are fundamentally incompatible with any local realistic theory. In other words, an experiment can be done that can rule out all theories based on local hidden variables. In 2015 one of the first complete experimental tests of Bell's inequalities was carried out at the National Institute of Standards and Technology by my team. Using this Bell test experiment it is possible to build a random number generator whose uniformity can be self-certified. Such a random number generator that can trace its roots back to the original Einstein thought experiments is the closest we can get to “throwing God’s dice.” I'll discuss our recent effort to turn this source of certified randomness into a public service.
3:30 pm, Friday, November 10, 2023
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