Information heat engine: converting information to energy by feedback control

TL;DR

This paper experimentally demonstrates a Szilard-type information-to-energy conversion using real-time feedback control on a Brownian particle, verifying a fundamental principle of the information-heat engine.

Contribution

It provides the first experimental realization of converting information into energy via feedback control, confirming theoretical predictions.

Findings

Achieved free energy gain exceeding work input through feedback manipulation.

Verified the generalized Jarzynski equality in a nonequilibrium setting.

Demonstrated a practical implementation of an information-heat engine.

Abstract

In 1929, Leo Szilard invented a feedback protocol in which a hypothetical intelligence called Maxwell's demon pumps heat from an isothermal environment and transduces it to work. After an intense controversy that lasted over eighty years; it was finally clarified that the demon's role does not contradict the second law of thermodynamics, implying that we can convert information to free energy in principle. Nevertheless, experimental demonstration of this information-to-energy conversion has been elusive. Here, we demonstrate that a nonequilibrium feedback manipulation of a Brownian particle based on information about its location achieves a Szilard-type information-energy conversion. Under real-time feedback control, the particle climbs up a spiral-stairs-like potential exerted by an electric field and obtains free energy larger than the amount of work performed on it. This enables us to verify the generalized Jarzynski equality, or a new fundamental principle of "information-heat engine" which converts information to energy by feedback control.