We study numerically the role of hydrodynamics in the liquid-hexatic transition of active colloids at intermediate activity, where motility induced phase separation (MIPS) does not occur. We show that in the case of active Brownian particles (ABP), the critical density of the transition decreases upon increasing the particle’s mass, enhancing ordering, while self-propulsion has the opposite effect in the activity regime considered. Active hydrodynamic particles (AHP), instead, undergo the liquid-hexatic transition at higher values of packing fraction \(\phi \) than the corresponding ABP, suggesting that hydrodynamics have the net effect of disordering the system. At increasing densities, close to the hexatic-liquid transition, we found in the case of AHP the appearance of self-sustained organized motion with clusters of particles moving coherently.

我们以数值方式研究了流体动力学在中间活性胶体的液体-六方相转变中的作用，其中不发生运动诱导相分离（MIPS）。我们表明，在活跃布朗粒子（ABP）的情况下，转变的临界密度随着粒子质量的增加而降低，从而增强有序性，而自推进在所考虑的活动状态中具有相反的效果。相反，活性流体动力学粒子（AHP）在比相应的 ABP 更高的堆积分数\(\phi \)值下经历液体-六方相变，这表明流体动力学具有扰乱系统的净效应。在密度增加时，接近六方-液体转变，我们发现在层次分析法的情况下，出现了自维持有组织的运动，粒子簇一致地运动。