Onsager reciprocal relations
= Onsager reciprocal relations
{wiki=Onsager_reciprocal_relations}
Onsager reciprocal relations are fundamental principles in nonequilibrium thermodynamics that describe the behavior of systems close to thermal and chemical equilibrium. These relations, formulated by the physicist Lars Onsager in the 1930s, express a profound symmetry in the response of a system to perturbations.