1306.0314 (U. Dorner)

Noise assisted Ramsey interferometry    [PDF]

U. Dorner

We present a method for improving the precision of estimating an atomic transition frequency via Ramsey interferometry without relying on entanglement in the presence of correlated dephasing which is highly relevant in experimental setups using strings of trapped ions. The improvement is gained by allowing the noise to transform an initial product state into a complex stationary state which we use for Ramsey interferometry. The improvement is not an improvement in scaling, i.e. the estimation precision has the same scaling with the number of atoms as the standard quantum limit, but an improvement by a constant factor which is dominated by the free evolution time in the Ramsey interferometer. Since we use a stationary state this evolution time can be substantially larger than in conventional Ramsey interferometry which is limited by the coherence time of the atoms.

View original: http://arxiv.org/abs/1306.0314