title: Symmetry group and group representations associated with the thermodynamic covariance principle.
abstract: The main objective of this work [previously appeared in literature, the thermodynamical field theory (TFT)] is to determine the nonlinear closure equations (i.e., the flux-force relations) valid for thermodynamic systems out of Onsager's region. The TFT rests upon the concept of equivalence between thermodynamic systems. More precisely, the equivalent character of two alternative descriptions of a thermodynamic system is ensured if, and only if, the two sets of thermodynamic forces are linked with each other by the so-called thermodynamic coordinate transformations (TCT). In this work, we describe the Lie group and the group representations associated to the TCT. The TCT guarantee the validity of the so-called thermodynamic covariance principle (TCP): The nonlinear closure equations, i.e., the flux-force relations, everywhere and in particular outside the Onsager region, must be covariant under TCT. In other terms, the fundamental laws of thermodynamics should be manifestly covariant under transformations between the admissible thermodynamic forces, i.e., under TCT. The TCP ensures the validity of the fundamental theorems for systems far from equilibrium. The symmetry properties of a physical system are intimately related to the conservation laws characterizing that system. Noether's theorem gives a precise description of this relation. We derive the conserved (thermodynamic) currents and, as an example of calculation, a system out of equilibrium (tokamak plasmas) where the validity of TCP imposed at the level of the kinetic equations is also analyzed.
authors.affiliation: Department of Theoretical Physics and Mathematics, Université Libre de Bruxelles (U.L.B.), Campus Plaine C.P. 231, Bvd du Triomphe, 1050 Brussels, Belgium.|Royal Military School (RMS), Av. de la Renaissance 30, 1000 Brussels, Belgium.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Sonnino
authors.affiliation: High Energy Nuclear Physics Group, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China.
authors.forename: Jarah
authors.initials: J
authors.lastname: Evslin
authors.affiliation: Department of Computer Science, University College London (UCL), Gower St, WC1E 6BT London, United Kingdom.
authors.forename: Alberto
authors.initials: A
authors.lastname: Sonnino
authors.affiliation: Physics Department, University of Craiova, Str. A. I. Cuza 13 200585 Craiova, Romania.
authors.forename: György
authors.initials: G
authors.lastname: Steinbrecher
authors.affiliation: Departamento de Física, Facultad de Ciencias Físicas y Mathemáticas, Universidad de Chile, Casilla 487-3 Santiago de Chile, Chile.
authors.forename: Enrique
authors.initials: E
authors.lastname: Tirapegui