Casimir Forces in a Piston Geometry at Zero and Finite Temperatures

Understand

We study Casimir forces on the partition in a closed box (piston) with perfect metallic boundary conditions.

• Related closed geometries have generated interest as candidates for a repulsive force.
• By using an optical path expansion we solve exactly the case of a piston with a rectangular cross section, and find that the force always attracts the partition to the nearest base.
• For arbitrary cross sections, we can use an expansion for the density of states to compute the force in the limit of small height to width ratios.