Exotic force seen for first time

For the first time, researchers have measured a long-theorized force that operates at distances so tiny they’re measured in billionths of a meter, which may have important applications in nanotechnology as scientists and engineers seek new ways to create devices too small for the eye to see.

The advance, by researchers from Harvard University and the National Institutes of Health (NIH), used a novel combination of materials to create a repulsive Casimir force, which pushes apart certain materials when separated by distances so tiny — between 20 nanometers and 100 nanometers — that they’re nearly touching.

The force, which decreases in strength as the distance between the two materials increases, may provide a new means to build ultra-low friction and other nanoscale devices, such as new types of compasses, accelerometers, and gyroscopes.

“Repulsive Casimir forces are of great interest since they can be used in new ultra-sensitive force and torque sensors to levitate an object immersed in a fluid at nanometric distances above a surface,” said Federico Capasso, Robert L. Wallace Professor of Applied Physics at Harvard’s School of Engineering and Applied Sciences (SEAS), who led the study. “Further, these objects are free to rotate or translate relative to each other with minimal static friction because their surfaces never come into direct contact.”