2017/02/28 by Giorgio Colangelo, Ferran Martin Ciurana, Lorena C. Bianchet +2 · 1 citation
Physics and Astronomy · #quant-ph #physics.atom-ph
paper · pdf · doi:10.1038/nature21434
published as Nature 543, 525-528 (2017) · 12 pages, 7 figures
arxiv created 2017/02/28 · arxiv updated 2017/03/24
We show how simultaneous, back-action evading tracking of non-commuting observables can be achieved in a widely-used sensing technology, atomic interferometry. Using high-dynamic-range dynamically-decoupled quantum non-demolition (QND) measurements on a precessing atomic spin ensemble, we track the collective spin angle and amplitude with negligible effects from back action, giving steady-state tracking sensitivity 2.9 dB beyond the standard quantum limit and 7.0 dB beyond Poisson statistics.