title: Weakly and strongly consistent formulations of irreversible processes.
abstract: If time-evolution equations are formulated in terms of thermodynamic building blocks, two possibilities arise to judge the consistency of models: By the properties of the building blocks (strong or structural consistency), or solely by the implied evolution equations (weak or dynamic consistency). We propose a straightforward procedure to check for strong consistency by means of the eigenvalues and eigenmodes of the linearized equations, which is related to establishing a fluctuation-dissipation theorem. By applying the general ideas to hydrodynamics, we clarify the role of the controversial diffusion terms in hydrodynamic equations.
authors.affiliation: ETH Zürich, Department of Materials, Polymer Physics, HCI H 543, CH-8093 Zürich, Switzerland. hco@mat.ethz.ch
authors.forename: Hans Christian
authors.initials: HC
authors.lastname: Ottinger