Some solids can be stirred. Researchers have shown that a bizarre quantum state of matter that is both a solid and a frictionless fluid at the same time can be agitated, apparently creating a series of tiny vortices inside the material. The experiment is evidence of the progress being made in understanding the strange properties of so-called “supersolids”.
“I’ve never done, in all my life, such a challenging experiment,” says Francesca Ferlaino at the University of Innsbruck in Austria. In 2022, she and her colleagues became the…