1306.5065 (Dong Xie et al.)

Precision frequency metrology in Correlated Environments    [PDF]

Dong Xie, An Min Wang

We mainly explore precision bounds of frequency measurements in correlated environments. In standard Ramsey spectroscopy setup, the metrological equivalence of product and maximally entangled states that holds in uncorrelated Markovian environments fails in uncorrelated non-Markovian environments. We demonstrate that it persists in maximally correlated Markovian and non-Markovian environments. A variational approach is used to analytically get the precision bounds in correlated Markovian and Non-Markovian environments. The optimal measurement can achieve a much higher resolution than standard Ramsey spectroscopy in the correlated environments. We find that in correlated Markovian and general non-Markovian environments, when the number of particles in the maximally entangled states is even, the precision bounds decreases with interrogation time; when the number is odd, the precision bounds is independent of interrogation time. And the opposite case appears in some special non-Markovian environments.

View original: http://arxiv.org/abs/1306.5065