Feedback control of coherent spin states using weak nondestructive measurements
LANDRAGIN, A.
Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace [LNE - SYRTE]
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Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace [LNE - SYRTE]
Langue
en
Article de revue
Ce document a été publié dans
Physical Review A : Atomic, molecular, and optical physics [1990-2015]. 2014-06, vol. 89, n° 6, p. 063619
American Physical Society
Résumé en anglais
We consider the decoherence of a pseudo-spin ensemble under collective random rotations, and study, both theoretically and experimentally, how a nondestructive measurement combined with real-time feedback correction can ...Lire la suite >
We consider the decoherence of a pseudo-spin ensemble under collective random rotations, and study, both theoretically and experimentally, how a nondestructive measurement combined with real-time feedback correction can protect the state against such a decoherence process. We theoretically characterize the feedback efficiency with different parameters --- coherence, entropy, fidelity --- and show that a maximum efficiency is reached in the weak measurement regime, when the projection of the state induced by the measurement is negligible. This article presents in detail the experimental results published in [Phys. Rev. Lett. \textbf{110}, 210503 (2013)], where the feedback scheme stabilizes coherent spin states of trapped ultra-cold atoms, and nondestructively probed with a dispersive optical detection. In addition, we study the influence of several parameters, such as atom number and rotation angle, on the performance of the method. We analyze the various decoherence sources limiting the feedback efficiency and propose how to mitigate their effect. The results demonstrate the potential of the method for the real-time coherent control of atom interferometers.< Réduire
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