Phys. Rev. Lett. 108, 230403 (2012)

A surprising consequence of Heisenberg's uncertainty principle is that something can be created from nothing. Hawking radiation and the dynamical Casimir effect are examples of the macroscopic manifestation of quantum vacuum fluctuations — near black-hole event horizons or accelerating boundaries, photons pop out of the vacuum. Such spontaneous emission is also expected to occur in the presence of spinning bodies: Mohammad Maghrebi and colleagues have uncovered a new twist.

Spontaneous emission from rotating objects was predicted in the 1970s, but Maghrebi et al. have revisited the theory and introduced an exact theoretical treatment of vacuum fluctuations in the presence of a spinning body. Their scattering-theory approach not only confirms that energy is emitted by the spinning object even at zero temperature, but also signals a previously unknown effect: the radiation from a rotating body exerts pressure on a nearby test object, which is dragged along and starts rotating parallel to the rotation axis. A similar effect is expected for the generalization to relativistic motion.