Cooling a small floating object to near absolute zero could reveal quantum behavior at a macroscopic level. One way to achieve this cooldown is by coupling the object’s motion to its magnetic spins. In this approach, repeatedly aligning the spins causes them to absorb more and more energy from the motion, gradually cooling the object. Throughout this process, the spins must be coherent—that is, in a well-defined quantum state—and the challenge has been to attain a sufficiently long coherence time. Now Gabriel Hétet and his colleagues at the École Normale Supérieure, France, have applied nuclear magnetic resonance (NMR) techniques to a microscopic levitating diamond [1]. The researchers achieved a spin coherence time that was more than 1000 times longer than previous records for levitating objects.
To read more, click here.