Onsager, L.

Lars Onsager was a renowned Danish-American physicist who made groundbreaking contributions to thermodynamics and statistical mechanics. His most famous achievement is the formulation of the reciprocal relations in irreversible thermodynamics, which describe how certain properties of systems not in equilibrium are interconnected. These principles help us understand how energy and matter flow in natural and engineered systems, such as in chemical reactions, heat transfer, and biological processes. Onsager's work provided a unifying framework for analyzing systems driven far from equilibrium, earning him the Nobel Prize in Chemistry in 1968.