Building a global quantum network linking distant quantum resources will require the invention and development of new technologies. A basic building block of any such effort will be the efficient distribution of entanglement. One of the first non-trivial applications of a quantum network is to generate certifiable randomness using entanglement and a loophole-free Bell test–a task with no classical system can achieve.
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. Carrying out this test has been technologically challenging. It wasn’t until 2015 when three independent groups were able to rule out local realism in experiments free of loopholes. In this talk I will discuss the loophole-free Bell test carried out at the National Institute of Standards and Technology. I will also discuss how we can use such a Bell test to build a random number generator that can be certified by quantum mechanics itself. Such a random number generator that can trace its roots back to the original Einstein thought experiments, and is one of the building blocks of future quantum networks.
Topic: INQNET seminar
Time: June 15, 2020 12:30 PM Pacific Time (US and Canada)
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Meeting ID: 933 0458 4361
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