Researchers report the entanglement-enhanced measurement of a delicate material system, in which they non-destructively probe an 85Rb atomic spin ensemble by near-resonant Faraday rotation. They use narrowband, atom-resonant ‘NOON’ states to beat the standard quantum limit of sensitivity by more than five standard deviations, both on a per-photon and a per-damage basis.
- Florian Wolfgramm
- Chiara Vitelli
- Morgan W. Mitchell