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arXiv · 1101.3766

Quantum coherence between two atoms beyond Q=10^15

C. W. Chou·D. B. Hume·M. J. Thorpe·D. J. Wineland·T. Rosenband
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Abstract

We place two atoms in quantum superposition states and observe coherent phase evolution for 3.4x10^15 cycles. Correlation signals from the two atoms yield information about their relative phase even after the probe radiation has decohered. This technique was applied to a frequency comparison of two Al+ ions, where a fractional uncertainty of 3.7+1.0-0.8x10^-16/\sqrt{τ/s} was observed. Two measures of the Q-factor are reported: The Q-factor derived from quantum coherence is 3.4+2.4-1.1x10^16, and the spectroscopic Q-factor for a Ramsey time of 3 s is 6.7x10^15. As part of this experiment, we demonstrate a method to detect the individual quantum states of two Al+ ions in a Mg+-Al+-Al+ linear ion chain without spatially resolving the ions.

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C. W. Chou, D. B. Hume, M. J. Thorpe, D. J. Wineland, T. Rosenband. 2011-01-24. Quantum coherence between two atoms beyond Q=10^15. https://doi.org/10.1103/physrevlett.106.160801

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