In the Widom-Rowlinson lattice gas, two particle species (A, B) diffuse freely via particle-hole exchange, subject to both on-site exclusion and prohibition of A-B nearest-neighbor pairs. As an athermal system, the overall densities are the only control parameters. As the densities increase, an entropically driven phase transition occurs, leading to ordered states with A- and B-rich domains separated by hole-rich interfaces. Using Monte Carlo simulations, we analyze the effect of imposing a drive on this system, biasing particle moves along one direction. Our study parallels that for a driven Ising lattice gas -- the Katz-Lebowitz-Spohn (KLS) model, which displays atypical collective behavior, e.g., structure factors with discontinuity singularities and ordered states with domains only parallel to the drive. Here, other novel features emerge, including structure factors with kink singularities (best fitted to |q|), maxima at non-vanishing wavevector values, oscillating correlation functions, and ordering into multiple striped domains perpendicular to the drive, with a preferred wavelength depending on density and drive intensity. Moreover, the (hole-rich) interfaces between the domains are statistically rough (whether driven or not), in sharp contrast with those in the KLS model, in which the drive suppresses interfacial roughness. Defining a novel order parameter (to account for the emergence of multistripe states), we map out the phase diagram in the density-drive plane and present preliminary evidence for a critical phase in this driven lattice gas.
Microemulsions in the driven Widom-Rowlinson lattice gas
对二维Widom-Rowlinson格子气在外加驱动下的研究揭示了一个显著的非平衡稳态，其中垂直于驱动方向形成均匀的条纹（让人想起平衡层状相）[R. Dickman和R. K. P. Zia，Phys. Rev. E 97，062126（2018）]。在这里，我们研究这个模型在低颗粒密度的二维和三维，在那里我们发现一个无序的阶段与特征长度尺度（“微乳液”）沿驱动方向。我们发展了一个连续的理论，这个无序相，以获得一个粗粒度的非平衡动力学场论行动。该行动的形式有两个耦合的驱动扩散系统具有不同的特征速度，产生的粒子之间的相互作用的排斥和驱动。然后，我们将展示如何波动校正的场论可能会产生的微乳液相的特征，包括在静态结构因子对应的特征长度尺度的峰值。这项工作奠定了基础，了解条纹现象更普遍。
Pattern formation in a coupled driven diffusive system
Universidade Federal de Minas Gerais（米纳斯吉拉斯联邦大学）；Worcester State University（伍斯特州立大学）；University of Tennessee, Knoxville（田纳西大学诺克斯维尔分校）；University of Houston（休斯顿大学）
