Synopsis: Friction in a vacuum

Calculations show that vacuum electromagnetic fluctuations can be a source of rotational friction on a spinning particle.
Synopsis figure
Credit: Alejandro Manjavacas and Javier García de Abajo, Phys. Rev. A (2011)

In the Casimir effect, vacuum fluctuations of the electromagnetic field exert a force on closely spaced metal plates, a phenomenon that is well understood theoretically and detectable experimentally. Can a related effect occur for rotating systems, in which vacuum fluctuations alter the spin rate of a particle, resulting in rotational drag? Writing in Physical Review A, Alejandro Manjavacas and Javier García de Abajo of the Instituto de Óptica, Madrid, Spain, show theoretically that this should be an experimentally observable effect.

The phenomenon of vacuum friction for spinning objects is somewhat different than for the static parallel plates: the accelerating charges in a spinning conductive object interact with the vacuum fluctuations and can emit photons. Earlier work by Manjavacas and García de Abajo tackled the problem with a semiclassical model that employed the fluctuation-dissipation theorem to calculate the overall energy transfer between the spinning particle and the vacuum field. In their new calculations, they take a fully quantum mechanical approach, which not only confirms the semiclassical results but extends the results to molecular systems and magnetic interactions. In addition to their intrinsic interest, the findings may be relevant to understanding the dynamical behavior of cosmic nanoparticles such as interstellar dust and the optical spectra of rotating molecules. – David Voss


Features

More Features »

Announcements

More Announcements »

Subject Areas

Astrophysics

Previous Synopsis

Quantum Information

Reality, locality, and “free will”

Read More »

Next Synopsis

Gravitation

Making waves

Read More »

Related Articles

Synopsis: Cosmic Test of Quantum Mechanics
Quantum Physics

Synopsis: Cosmic Test of Quantum Mechanics

Light from two stars in the Milky Way has been used to test an open loophole of quantum physics. Read More »

Focus: Photons Brake the Sun
Plasma Physics

Focus: Photons Brake the Sun

Detailed solar observations and theory suggest that photons remove angular momentum from the Sun, explaining why the Sun’s surface spins more slowly than its core. Read More »

Viewpoint: New Clues as to Why Boyajian’s Star is Dimming
Statistical Physics

Viewpoint: New Clues as to Why Boyajian’s Star is Dimming

A statistical analysis links a star’s mysterious brightness fluctuations to internal nonequilibrium phenomena, rather than structures orbiting around the star. Read More »

More Articles