Informationthermodynamics

Informationthermodynamics is an interdisciplinary field that studies the relationship between information processing and thermodynamics. It investigates how information measures relate to energy, temperature, and entropy in physical systems, and how the lifecycle of information influences energetic costs in computation and communication.

Historically, the topic emerged from questions raised by Maxwell's demon and the Szilard engine, which suggested that information could influence physical entropy. A key milestone is Landauer's principle, which states that erasing a bit of information dissipates at least kB T ln 2 of energy, tying logical irreversible operations to thermodynamic cost. This framework connects information theory with thermodynamics and provides a basis for understanding limits on computation.

The theoretical foundation blends statistical mechanics with information theory. Entropy notions from Boltzmann and Gibbs are linked to Shannon information, and the second law is applied to the total system, including information storage. The idea is that information processing cannot be thermodynamically free; irreversible operations inherently generate entropy, while reversible processes can in principle minimize energy dissipation.

Core concepts include reversible computing, the role of feedback and measurement, and the use of mutual information to bound extractable work in certain setups. Stochastic thermodynamics and fluctuation theorems offer tools for analyzing small or fluctuating systems where individual events matter, and they help quantify the energetic implications of information flows.

Applications span energy-efficient computing, nanoscale machines, and biological processes where information handling interacts with thermal fluctuations. In quantum contexts, informationthermodynamics informs the costs and limits of quantum information processing and measurement, highlighting ongoing questions about the ultimate physical bounds of information processing.