In one minute

The Casimir effect, driven by quantum and thermal fluctuations, is well known for creating forces between closely spaced surfaces. Benjamin Spreng and Jeremy Munday study the related Casimir torque, which rotates optically anisotropic surfaces relative to each other. They examine, for the first time, how thermal fluctuations affect the torque between birefringent plates. Thermal modes reduce the torque substantially, by up to 2 orders of magnitude for strongly birefringent materials. Temperature also bends the torque's angular dependence away from the usual sinusoidal form, especially beyond the thermal wavelength. Pairs of dissimilar plates whose torque reverses with distance allow temperature to control both its size and direction, a design handle for nanoscale sensors.

Thermal Effects in the Casimir Torque between Birefringent Plates