Quantum electrodynamical torques in the presence of Brownian motion

Quantum fluctuations of the electromagnetic field give rise to a zeropoint energy that persists even in the absence of electromagnetic sources. One striking consequence of the zero-point energy is manifested in the Casimir force, which causes two electrically neutral metallic plates to attract in order to reduce the zero-point energy. A second, less well-known, effect is a torque that arises between two birefringent materials with in-plane optical anisotropy as a result of the zero-point energy. In this paper, we discuss the influence of Brownian motion on two birefringent plates undergoing quantum electrodynamical (QED) rotation as a result of the system’s zero-point energy. Direct calculations for the torque are presented, and preliminary experiments are discussed. 4 Author to whom any correspondence should be addressed. New Journal of Physics 8 (2006) 244 PII: S1367-2630(06)27240-9 1367-2630/06/010244+13$30.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft 2 Institute of Physics DEUTSCHE PHYSIKALISCHE GESELLSCHAFT