Casimir Piston Research Articles

Casimir piston and cylinder, perturbatively

According to perturbation theory, a thin piston in a thin-walled semi-infinite cylinder closed at its head, both weakly reflecting dielectrics, experiences a force which is directed towards the cylinder head at small separations $a$, but which changes sign as $a$ rises. By contrast, for thick enough material the force remains attractive for all $a$ (as it does for perfect reflection, according to the recent paper by Hertzberg et al. [M. P. Hertzberg, R. L. Jaffe, M. Kardar, and A. Scardicchio, Phys. Rev. Lett. 95, 250402 (2005)]).