Nonmonotonic effects of nonreciprocal interactions on glass transition and diffusion in a two-dimensional emergent active system

The glass transition of supercooled liquids poses a significant challenge in statistical physics. Although the glass transition has been extensively investigated in various active systems, the influence of nonreciprocal interactions between particles on this transition remains an open question. In this study, we investigate the diffusion and glass transition within a two-dimensional Kob-Andersen mixture featuring nonreciprocal particle interactions. Our findings reveal that nonreciprocity among particles profoundly impacts the system's dynamics. Specifically, in the gaseous or high-temperature liquid phase, the diffusion coefficient exhibits a consistent increase with rising nonreciprocity. However, in the viscous liquid or glassy state, the emergence of large-scale directed motion leads to a weakly nonmonotonic relationship between the diffusion coefficient and nonreciprocity. As nonreciprocity increases, the diffusion coefficient experiences a decline, reaching a minimum at finite nonreciprocity. Under dense conditions and at low temperatures, the system undergoes a transition between the glassy and liquid states by modulating nonreciprocity. However, at high temperatures, nonreciprocity becomes less significant, and this transition cannot be achieved by changing nonreciprocity. Our findings shed light on the intricate interplay between particle interactions and system dynamics in the context of glass transition phenomena.