title: Nonequilibrium Casimir Force with a Nonzero Chemical Potential for Photons.
abstract: We introduce a new class of nonequilibrium Casimir forces, where the deviation from equilibrium is achieved through the use of a nonzero chemical potential of photons. Such a force can be observed when two semiconductors are brought in close proximity to each other, and when at least one of the semiconductors is subject to an external voltage. By exact numerical calculations of a sphere-plate configuration, we show that in the total force the non-equilibrium component can dominate over its equilibrium counterpart with a relatively modest external voltage, even when the sphere-plate separation is in the nanoscale. As a result, repulsion can be achieved at the nanoscale even with a relatively modest applied voltage. The results here point to a pathway that can significantly advance the quest for observing and harnessing nonequilibrium Casimir forces in solid-state systems.
authors.affiliation: Department of Applied Physics, Stanford University, California 94305, USA.|Department of Electrical Engineering, Ginzton Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: Kaifeng
authors.initials: K
authors.lastname: Chen
authors.affiliation: Department of Electrical Engineering, Ginzton Laboratory, Stanford University, Stanford, California 94305, USA.
authors.forename: Shanhui
authors.initials: S
authors.lastname: Fan