In optomechanical experiments, researchers routinely observe quantum effects in macroscopic objects. Recent examples include the ground-state cooling of mechanical oscillators as heavy as hundreds of nanograms. To date, these demonstrations only involved solids or ultracold gases. Now, a team led by Jack Harris of Yale University and Jakob Reichel of the Kastler–Brossel Laboratory, France, has provided the first evidence of quantum optomechanical effects in a liquid—superfluid helium. The approach may allow researchers to explore novel optomechanical regimes in liquids and to answer outstanding questions on superfluidity.

To read more, click here.