Scientists identify unusual force acting on nanoparticles

Recently, physicists were able to measure the Casimir Effect, an unusual force acting on the smallest of particles. The force is created by interactions between the electromagnetic waves of particles in a vacuum.

Classical physics fails to account for the unique force. Instead, researchers relied on quantum field theory to interpret their observations.

"These studies are important because we are developing nanotechnologies where we're getting into distances and sizes that are so small that these types of forces can dominate everything else," Alejandro Manjavacas, a physics professor at the University of New Mexico, said in a news release. "We know these Casimir forces exist, so, what we're trying to do is figure out the overall impact they have on very small particles."

Through their research, Manjavacas and an international team of researchers were able to describe the Casimir Effect using an analogy between classical physics and quantum field theory.

The sea of photons inside the vacuum affect a spinning nanoparticle much the way friction affects a ball hitting another surface. The photons both slow the particle's spin and enact a later force on it -- only there is no actual contact between the photons and the nanoparticle.

"The nanoparticle experiences a lateral force as if it were in contact with the surface, even though is actually separated from it," said Manjavacas. "It's a strange reaction but one that may prove to have significant impact for engineers."

Experiments showed changes in the distance between a particle and the surface alter the strength and direction of the Casimir Effect. The new observations, detailed in the journal Physical Review Letters, could help scientists improve nanotechnologies for industries like healthcare and electronics.