Photonic Maxwell's Demon.
Abstract:
We report an experimental realization of Maxwell's demon in a photonic setup. We show that a measurement at the few-photons level followed by a feed-forward operation allows the extraction of work from intense thermal light into an electric circuit. The interpretation of the experiment stimulates the derivation of an equality relating work extraction to information acquired by measurement. We derive a bound using this relation and show that it is in agreement with the experimental results. Our work puts forward photonic systems as a platform for experiments related to information in thermodynamics.In situ characterization of an optically thick atom-filled cavity
Abstract:
A means for precise experimental characterization of the dielectric susceptibility of an atomic gas inside an optical cavity is important for the design and operation of quantum light-matter interfaces, particularly in the context of quantum information processing. Here we present a numerically optimized theoretical model to predict the spectral response of an atom-filled cavity, accounting for both homogeneous and inhomogeneous broadening at high optical densities. We investigate the regime where the two broadening mechanisms are of similar magnitude, which makes the use of common approximations invalid. Our model agrees with an experimental implementation with warm caesium vapor in a ring cavity. From the cavity response, we are able to extract important experimental parameters, for instance the ground-state populations, total number density, and the magnitudes of both homogeneous and inhomogeneous broadening.