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DOE OSTI · 1982806

Microemulsions in the driven Widom-Rowlinson lattice gas

Lavrentovich, Maxim O.·Dickman, Ronald·Zia, R. K. P.
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Abstract

An investigation of the two-dimensional Widom-Rowlinson lattice gas under an applied drive uncovered a remarkable nonequilibrium steady state in which uniform stripes (reminiscent of an equilibrium lamellar phase) form perpendicular to the drive direction [R. Dickman and R. K. P. Zia, Phys. Rev. E 97, 062126 (2018)]. Here we study this model at low particle densities in two and three dimensions, where we find a disordered phase with a characteristic length scale (a “microemulsion”) along the drive direction. Further we develop a continuum theory of this disordered phase to derive a coarse-grained field-theoretic action for the nonequilibrium dynamics. The action has the form of two coupled driven diffusive systems with different characteristic velocities, generated by an interplay between the particle repulsion and the drive. We then show how fluctuation corrections in the field theory may generate the characteristic features of the microemulsion phase, including a peak in the static structure factor corresponding to the characteristic length scale. This work lays the foundation for understanding the stripe phenomenon more generally.

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71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICSFluctuations & noiseMean-field & cluster methodsMonte Carlo methodsNonequilibrium lattice modelsNonequilibrium statistical mechanicsPerturbation theoryPhase separationPhysicsStatistical field theoryStochastic processes

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Lavrentovich, Maxim O., Dickman, Ronald, Zia, R. K. P.. 2021-12-27. Microemulsions in the driven Widom-Rowlinson lattice gas. https://doi.org/10.1103/physreve.104.064135

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