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arXiv · 2312.13960

Probing pair correlations in Fermi gases with Ramsey-Bragg interferometry

Théo Malas-Danzé·Alexandre Dugelay·Nir Navon·Hadrien Kurkjian
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Abstract

We propose an interferometric method to probe pair correlations in a gas of spin-1/2 fermions. The method consists of a Ramsey sequence where both spin states of the Fermi gas are set in a superposition of a state at rest and a state with a large recoil velocity. The two-body density matrix is extracted via the fluctuations of the transferred fraction to the recoiled state. In the pair-condensed phase, the off-diagonal long-range order is directly reflected in the asymptotic behavior of the interferometric signal for long interrogation times. The method also allows to probe the spatial structure of the condensed pairs: the interferometric signal is an oscillating function of the interrogation time in the Bardeen-Cooper-Schrieffer regime; it becomes an overdamped function in the molecular Bose-Einstein condensate regime.

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Théo Malas-Danzé, Alexandre Dugelay, Nir Navon, Hadrien Kurkjian. 2023-12-21. Probing pair correlations in Fermi gases with Ramsey-Bragg interferometry. https://doi.org/10.21468/scipostphys.17.1.024

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