Room Temperature Quantum Entanglement Achieved With Levitating Glass Nanosphere

Physicists at the University of Florence generated persistent quantum entanglement between the motion of a levitating 100-nanometer glass bead and a beam of light. The microscopic sphere contains tens of millions of atoms and is confined in a near-vacuum chamber using a tightly focused optical tweezer. The team bypassed traditional cryogenic cooling by using two distinct lasers—one red-detuned laser to cool the sphere's motion to its ground state, and a blue-detuned laser to entangle that motion with the light itself. The entangled light physically exits the optical cavity, establishing a traveling quantum system that can carry correlations to other physical locations. "A field that exists only inside a cavity is difficult to use as a quantum resource elsewhere. Once the light leaves the cavity, however, it becomes a traveling quantum system." — Francesco Marin