Controlling the reverse thermodiffusion in dumbbell-shaped active particle systems

The anomalous transport phenomena of active particles under temperature gradients pose a significant challenge to classical statistical mechanics. In-depth studies of such anomalous thermodiffusion behaviors are essential for understanding and regulating the mass and energy transport mechanisms of active particles. This paper utilizes molecular dynamics simulations to investigate the mass transport of dumbbell-shaped active particles in a system with a specific temperature difference. The results indicate that when the self-propulsion force is sufficiently large, active particles can defy convention and diffuse from the low-temperature region to the high-temperature region, demonstrating the phenomenon of reverse thermodiffusion (RTD). Specifically, the lower the system's average temperature, the more readily the particles undergo RTD; conversely, the higher the average temperature, the more challenging it becomes. Additionally, the asymmetry of dumbbell-shaped particles significantly affects RTD behavior. The findings of this study provide a theoretical basis for the precise manipulation of active particle transport under temperature gradients and establish a theoretical foundation for practical applications such as efficient energy utilization and precise drug delivery.