Transport phenomena and Green-Kubo relations in active media: Simulation

We compute the viscous transport coefficients of an active fluid composed of chirally rotated dumbbells with molecular dynamics simulations. We use recently obtained Green-Kubo relations to calculate the emergent viscous transport coefficients (for details see accompanying Theory talk), and find that odd viscosity arises due to the breaking of time-reversal symmetry at the level of stress correlations. We demonstrate agreement between viscosity coefficients obtained from Green-Kubo relations and non-equilibrium molecular dynamics simulations with imposed shear. This verifies the Green-Kubo relations derived using the application of Onsager’s regression hypothesis to non-equilibrium steady states of active systems, and provides an impetus for developing the theory of non-equilibrium thermodynamics of active media.

References:
Epstein, J. M., & Mandadapu, K. K.; arXiv; 2019
Klymko, K., Mandal, D., & Mandadapu, K. K.; Journal of Chemical Physics; 147, 194109, 2017