Prof. John Bechhoefer (Department of Physics, Simon Fraser University, Burnaby, BC)

"What can Maxwell’s demon do? Experimental performance limits for information fueled engines"

Abstract: Information engines are a modern realization of the Maxwell demon thought experiment. They exploit “favorable fluctuations” of a heat bath to generate work, at the cost of dissipation in a measuring device. We designed a simple information engine using optical tweezers and feedback to raise a “heavy” micron-sized trapped bead diffusing in water against gravity, without doing any external work. We explore what limits the performance of this new type of motor and find, most significantly, that placing the bead in an environment with “extra” nonequilibrium fluctuations can dramatically increase power output. These experiments suggest that what was once a mere thought experiment may have practical applications.