Thermodynamics of information and control: the legacies of Maxwell, Szilard, and Landauer

Synopsis

Exactly one hundred and fifty years ago, Maxwell’s demon posed a fundamental challenge to the newly developed field of statistical physics-archive.  Just two months after its appearance, 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 theory.  Here, I will present an experiment that unites the two:  using feedback to make “impossible” dynamics, we create a Maxwell demon that can reach the fundamental limits to control set by thermodynamics.  In a Szilard engine, we test—and then extend—Rolf Landauer’s 1961 prediction that information erasure dissipates heat to compensate the work extracted 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.