Relativity of Observation: Operational Intensive Variables in Nonequilibrium Thermodynamics

We formulate nonequilibrium thermodynamics in which intensive variables acquire operational meaning through measurement protocols consistent with local reciprocity. Using physical equilibrium as a reference, conjugate observables are constructed by continuously adjusting devices along the local tangent space of the statistical manifold. In this relativity of observation, Onsager reciprocity holds locally, allowing inference-based Lagrange multipliers to be directly measured. This provides a systematic method to extend operational definitions of intensive variables to nonequilibrium states, highlighting their context-dependent nature and offering a concrete experimental strategy.

💡 Research Summary

The paper proposes a novel operational framework for intensive variables in nonequilibrium thermodynamics, grounded in an inference‑based formulation that treats intensive parameters as directly measurable quantities rather than abstract Lagrange multipliers. Starting from a reference equilibrium distribution Q(ω), the authors minimize the relative entropy D(P‖Q) under constraints on the averages of extensive observables M_i(ω), obtaining the exponential family P*_m(ω)=Z⁻¹(λ)Q(ω)exp