Stresses in non-equilibrium fluids: Exact formulation and coarse-grained theory
KRÜGER, Matthias
Max Planck Institute for Intelligent Systems [Tübingen]
4th Institute for Theoretical Physics
Max Planck Institute for Intelligent Systems [Tübingen]
4th Institute for Theoretical Physics
DÉMERY, Vincent
Laboratoire de Physique de l'ENS Lyon [Phys-ENS]
Laboratoire de Physico-Chimie Théorique [LPCT]
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Laboratoire de Physique de l'ENS Lyon [Phys-ENS]
Laboratoire de Physico-Chimie Théorique [LPCT]
KRÜGER, Matthias
Max Planck Institute for Intelligent Systems [Tübingen]
4th Institute for Theoretical Physics
Max Planck Institute for Intelligent Systems [Tübingen]
4th Institute for Theoretical Physics
DÉMERY, Vincent
Laboratoire de Physique de l'ENS Lyon [Phys-ENS]
Laboratoire de Physico-Chimie Théorique [LPCT]
Laboratoire de Physique de l'ENS Lyon [Phys-ENS]
Laboratoire de Physico-Chimie Théorique [LPCT]
ROHWER, Christian
Max Planck Institute for Intelligent Systems [Tübingen]
4th Institute for Theoretical Physics
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Max Planck Institute for Intelligent Systems [Tübingen]
4th Institute for Theoretical Physics
Langue
en
Article de revue
Ce document a été publié dans
Journal of Chemical Physics. 2018, vol. 148, n° 8, p. 084503
American Institute of Physics
Résumé en anglais
Starting from the stochastic equation for the density operator, we formulate the exact (instantaneous) stress tensor for interacting Brownian particles and show that its average value agrees with expressions derived ...Lire la suite >
Starting from the stochastic equation for the density operator, we formulate the exact (instantaneous) stress tensor for interacting Brownian particles and show that its average value agrees with expressions derived previously. We analyze the relation between the stress tensor and forces due to external potentials and observe that, out of equilibrium, particle currents give rise to extra forces. Next, we derive the stress tensor for a Landau-Ginzburg theory in generic, non-equilibrium situations, finding an expression analogous to that of the exact microscopic stress tensor, and discuss the computation of out-of-equilibrium (classical) Casimir forces. Subsequently, we give a general form for the stress tensor which is valid for a large variety of energy functionals and which reproduces the two mentioned cases. We then use these relations to study the spatio-temporal correlations of the stress tensor in a Brownian fluid, which we compute to leading order in the interaction potential strength. We observe that, after integration over time, the spatial correlations generally decay as power laws in space. These are expected to be of importance for driven confined systems. We also show that divergence-free parts of the stress tensor do not contribute to the Green-Kubo relation for the viscosity.< Réduire
Project ANR
Interactions induites par des fluctuations entre interfaces molles dans les systèmes complexes
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