Mysterious quantum forces unraveled
Discovered in 1948, Casimir forces are complicated quantum forces that affect only objects that are very, very close together. They’re so subtle that for most of the 60-odd years since their discovery, engineers have safely ignored them. But in the age of tiny electromechanical devices like the accelerometers in the iPhone or the micromirrors in digital projectors, Casimir forces have emerged as troublemakers, since they can cause micromachines’ tiny moving parts to stick together. MIT researchers have developed a powerful new tool for calculating the effects of Casimir forces, with ramifications for both basic physics and the design of microelectromechanical systems (MEMS). One of the researchers’ most recent discoveries using the new tool was a way to arrange tiny objects so that the ordinarily attractive Casimir forces become repulsive. If engineers can design MEMS so that the Casimir forces actually prevent their moving parts from sticking together — rather than...