We perform large-scale computer simulations of an off-lattice two-dimensional model of active particles undergoing a motility-induced phase separation (MIPS) to investigate the system's critical behaviour close to the critical point of the MIPS curve. By sampling steady-state configurations for large system sizes and performing finite size scaling analysis we provide exhaustive evidence that the critical behaviour of this active system belongs to the Ising universality class. In addition to the scaling observables that are also typical of passive systems, we study the critical behaviour of the kinetic temperature difference between the two active phases. This quantity, which is always zero in equilibrium, displays instead a critical behavior in the active system which is well described by the same exponent of the order parameter in agreement with mean-field theory.

中文翻译：

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活性颗粒的大规模非晶格模拟中运动引起的临界点的通用性类

我们执行活动性诱导相分离（MIPS）的活动粒子的非晶格二维模型的大规模计算机模拟，以研究系统的接近MIPS曲线临界点的临界行为。通过对大型系统的稳态配置进行采样并执行有限尺寸的缩放分析，我们提供了详尽的证据，表明该活动系统的关键行为属于Ising通用性类别。除了无源系统中常见的缩放比例观测值外，我们还研究了两个有源相之间动力学温差的临界行为。这个数量在平衡状态下始终为零，