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One hundred and fifty years ago, Maxwell's demon was first posed as a fundamental challenge to the newly developed field of statistical physics. Just two months later, Maxwell's paper "On governors" gave the first analysis of a feedback system. These two foundational works reflect the fundamental and practical aspects of control. Here, I will present an experiment that unites the two: using feedback to create `impossible' dynamics, we make a Maxwell demon that can reach the fundamental limits to control set by thermodynamics. We test - and then extend - Rolf Landauer's 1961 prediction that information erasure requires at least as much work as can be extracted from a system by virtue of information. These fundamental thermodynamic limits are benchmarks for evaluating the performance of practical information engines, such as those active within cells and other complex systems.

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John Bechhoefer, Simon Fraser University, Vancouver
TP seminar room 0.03
Contact: Joachim Krug