Scientists use quantum ’spooky action’ to entangle objects you can actually see

Even in the odd world of quantum physics, the phenomenon known as entanglement-in which two objects become tied together although not physically connected-is among the hardest to comprehend. It's equally difficult to achieve in the lab; scientists usually have to work very hard just to do it with single atoms. But a UChicago physicist is among a group of researchers that announced April 25 in Nature that they had managed to entangle perhaps the largest items yet, at a whopping 20 microns across-about the diameter of a single human hair. Scientists say that harnessing the mysterious property that Albert Einstein called "spooky action at a distance" is a crucial step toward exploiting quantum quirks for technology such as new kinds of sensors or computers. "Entanglement is not just some academic curiosity; it's also something you can harness as a basis for doing useful things with quantum mechanics," said Prof. Aashish Clerk of the University of Chicago's Institute for Molecular Engineering. Unfortunately for applications, entangled states are typically extremely fragile-especially so when they involve large objects. So Clerk and his former postdoc Matt Woolley (now at UNSW Sydney) developed a theoretical proposal for how to keep the motion of large objects entangled.