Laser light used to cool object to quantum ground state

Laser light used to cool object to quantum ground state: "We've taken a solid mechanical system—one made up of billions of atoms—and used optical light to put it into a state in which it behaves according to the laws of quantum mechanics. In the past, this has only been achieved with trapped single atoms or ions..."
As described in the paper, Painter and his colleagues have engineered a nanoscale object—a tiny mechanical silicon beam—such that laser light of a carefully selected frequency can enter the system and, once reflected, can carry thermal energy away, cooling the system.