Colloquium Schedule

Colloquium: Thursday, August 30, 4:10 PM, Lewis Lab 316

Random Numbers from Light: Photons, Chaos and Entropy

Rajarshi Roy

Many physical processes, including the intensity fluctuations of a chaotic laser, the detection of single photons, and the Brownian motion of a microscopic particle in a fluid are unpredictable, at least on long timescales. This unpredictability can be due to a  variety of physical mechanisms, but it is quantified by an entropy rate. This rate, which describes how quickly a system produces new and random information, is fundamentally important in statistical mechanics and practically important for random number generation. We experimentally study entropy generation and the emergence of deterministic chaotic dynamics from discrete noise in a system that applies feedback to a weak optical signal at the single-photon level. We show that in this system the dynamics transition from shot noise to chaos as the photon rate increases and that the entropy rate can reflect either the deterministic or noisy aspects of the system depending on the sampling rate and resolution of the measurements.

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Physics and Astronomy Colloquia are usually scheduled for Thursdays at 4:10 PM in Lewis Lab room 316. Refreshments and snacks are available in the nearby coffee room at 3:45 PM.

Physics Colloquium Schedule for FALL 2018

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