1202.2307 (P. Bushev et al.)

Continuous quantum measurement and phase locking of a single trapped ion    [PDF]

P. Bushev, G. Hetet, L. Slodicka, D. Rotter, M. A. Wilson, F. Schmidt-Kaler, J. Eschner, R. Blatt

We perform high-resolution real time read-out of the quantum motion of a
single trapped and laser cooled Ba+ ion. By using an interferometric setup we
demonstrate shot noise limited measurement of thermal oscillations with
resolution of 4 times the standard quantum limit. We also realize quantum
limited phase control of the ion motion, suppressing the photon recoil-induced
phase diffusion through a feedback loop. Due to the spectral narrowing in
phase-locked mode, the coherent ion oscillation is measured with resolution of
about 0.3 times the standard quantum limit.

View original: http://arxiv.org/abs/1202.2307