Researchers have discovered a Magnus-like contribution to the nonequilibrium Casimir-Polder force when a particle moves in vacuum near macroscopic bodies. This phenomenon arises from the interplay between particle dynamics and material-modified electromagnetic quantum fluctuations. The interaction induces a direction-dependent angular momentum in the particle, which then couples to the electromagnetic field's spin.

This interaction generates a drift force directly proportional to the cross product of the particle's angular and translational velocities. This finding reveals a rotational transport component within the nonequilibrium Casimir-Polder interaction. The Casimir-Polder force is a quantum effect describing the interaction between an atom or molecule and a surface, due to quantum fluctuations of the electromagnetic field.

The results establish a striking connection between forces induced by quantum fluctuations and the classical Magnus effect observed in fluid dynamics. The Magnus effect describes the force acting on a spinning object moving through a fluid, perpendicular to both the direction of motion and the axis of rotation. This parallel suggests that fundamental principles from fluid mechanics may have analogues in the realm of nonequilibrium quantum interactions.