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arXiv · 1407.8420

Protected subspace Ramsey spectroscopy

Laurin Ostermann·David Plankensteiner·Helmut Ritsch·Claudiu Genes
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Abstract

We study a modified Ramsey spectroscopy technique employing slowly decaying states for quantum metrology applications using dense ensembles. While closely positioned atoms exhibit superradiant collective decay and dipole-dipole induced frequency shifts, recent results [Ostermann, Ritsch and Genes, Phys. Rev. Lett. \textbf{111}, 123601 (2013)] suggest the possibility to suppress such detrimental effects and achieve an even better scaling of the frequency sensitivity with interrogation time than for noninteracting particles. Here we present an in-depth analysis of this 'protected subspace Ramsey technique' using improved analytical modeling and numerical simulations including larger 3D samples. Surprisingly we find that using sub-radiant states of $N$ particles to encode the atomic coherence yields a scaling of the optimal sensitivity better than $1/\sqrt{N}$. Applied to ultracold atoms in 3D optical lattices we predict a precision beyond the single atom linewidth.

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Laurin Ostermann, David Plankensteiner, Helmut Ritsch, Claudiu Genes. 2014-11-27. Protected subspace Ramsey spectroscopy. https://doi.org/10.1103/physreva.90.053823

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