Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
J Chem Phys. 2019 Feb 14;150(6):064905. doi: 10.1063/1.5085209.
We numerically examine mixtures of circularly moving and passive disks as a function of density and active orbit radius. For low or intermediate densities and/or small orbit radii, the system can organize into a reversible partially phase separated labyrinth state in which there are no collisions between disks, with the degree of phase separation increasing as the orbit radius increases. As a function of orbit radius, we find a divergence in the number of cycles required to reach a collision-free steady state at a critical radius, while above this radius, the system remains in a fluctuating liquid state. For high densities, the system can organize into a fully phase separated state that is mostly reversible, but collisions at the boundaries between the phases lead to a net transport of disks along the boundary edges in a direction determined by the chirality of the active disk orbits. We map the dynamic phases as a function of density and orbit radii and discuss the results in terms of the reversible-irreversible transition found in other periodically driven non-thermal systems. We also consider mixtures of circularly driven disks and ac driven disks where the ac drive is either in or out of phase with the circular motion and find a rich variety of pattern forming and reentrant disordered phases.
我们数值研究了作为密度和活性轨道半径函数的圆形运动和被动圆盘混合物。对于低或中等密度和/或小轨道半径，系统可以组织成一个可逆的部分相分离迷宫状态，其中圆盘之间没有碰撞，随着轨道半径的增加，相分离的程度增加。作为轨道半径的函数，我们发现达到无碰撞稳态所需的循环数在临界半径处发散，而在此半径以上，系统保持在波动的液体状态。对于高密度，系统可以组织成一个完全相分离的状态，该状态大部分是可逆的，但在相之间的边界处的碰撞会导致圆盘沿着边界边缘以由活性圆盘轨道的手性决定的方向进行净输运。我们绘制了作为密度和轨道半径函数的动态相图，并根据在其他周期性驱动非热系统中发现的可逆-不可逆转变来讨论结果。我们还考虑了圆形驱动圆盘和 ac 驱动圆盘的混合物，其中 ac 驱动与圆形运动同相或反相，发现了各种图案形成和再入无序相。
