Resolving An Individual One-Proton Spin Flip To Determine A Proton Spin State

Previous measurements with a single trapped proton (p) or antiproton ((p) over bar) detected spin resonance from the increased scatter of frequency measurements caused by many spin flips. Here a measured correlation confirms that individual spin transitions and states are rapidly detected instead. The 96% fidelity and an efficiency expected to approach unity suggests that it may be possible to use quantum jump spectroscopy to measure the p and (p) over bar magnetic moments much more precisely. DOI:10.1103/PhysRevLett.110.140406