In a vacuum, the Casimir–Lifshitz force causes friction effects that either hinder or may be exploited in nanomechanical device applications. So far, only attractive interactions have been measured, but theory predicts that when vacuum is replaced with certain media, the Casimir–Lifshitz force can also be repulsive. This effect is now experimentally confirmed in this study, which carefully chooses a system of interacting materials immersed in a fluid. The measured repulsive interaction is found to be weaker than the attractive force whereas in both cases the magnitude of the force increases with decreasing surface separation.
- J. N. Munday
- Federico Capasso
- V. Adrian Parsegian
