Casimir-Polder attraction and repulsion between nanoparticles and graphene in out-of-thermal-equilibrium conditions

The nonequilibrium Casimir-Polder force between a nanoparticle and a graphene sheet kept at different temperatures is investigated in the framework of a Dirac model using the formalism of the polarization tensor. It is shown that the force magnitude increases with increasing temperature of a graphene sheet. At larger separations an impact of nonequilibrium conditions on the force becomes smaller. According to our results, the attractive Casimir-Polder force vanishes at some definite nanoparticle-graphene separation and becomes repulsive at larger separations if the temperature of a graphene sheet is smaller than that of the environment. This effect may find applications both in fundamental investigations of graphene and for the control of forces in microdevices of bioelectronics.

Automated summary

In this study, the nonequilibrium Casimir-Polder force between a nanoparticle and a graphene sheet kept at different temperatures was examined using the formalism of the polarization tensor in the framework of a Dirac model. The results demonstrate that the magnitude of the force increases with the temperature of the graphene sheet. The impact of nonequilibrium conditions on the force becomes smaller at larger separations. Our findings reveal that for a graphene sheet with a lower temperature than the environment, the attractive Casimir-Polder force vanishes at a specific separation distance and becomes repulsive at larger distances. This effect has potential applications in fundamental graphene research and force control in bioelectronic microdevices.