According to a press release (14 February 2002), Umar Mohideen, associate professor of physics at the University of California-Riverside, has performed the first demonstration of the lateral Casimir force (a shape-dependent Casimir force) in his laboratory. His findings appeard in Physical Review Letters.
The Casimir force has its origins in virtual particles that exist in empty space. According to the release, the force acts tangential to two surfaces, resulting in a horizontal sliding motion of one surface against the other. This lateral force may make the movement of gears and motors in micromachines easier.