Laser & Optoelectronics Progress, Volume. 62, Issue 15, 1527001(2025)

Measurement of Contact in Strongly Interacting Fermi Gases

Xin Bao, Shuxian Yu, Zhijie Zhang, Shujin Deng*, and Haibin Wu
Author Affiliations
  • Institute of Quantum Science and Precision Measurement, East China Normal University, Shanhai200241, China
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    Contact is a universal thermodynamic quantity crucial for studying short-range pairing correlations in strongly interacting Fermi gases. It serves as a vital bridge connecting the system's microscopic short-range physics with its macroscopic thermodynamic properties. In this study, we developed a novel two-photon Raman coupling technique for strongly interacting ultracold Fermi gases. This method can switch the interaction to a non-interacting state on timescales much faster than the system's Fermi time, enabling instantaneous measurement of thermodynamic parameters. Our measurements reveal that in the high-momentum region, the atomic gas momentum distribution exhibits a 1/k4 scaling behavior characteristic of Contact, allowing precise determination of the Contact coefficient. Comparison of our experimental results with traditional RF spectroscopy methods and theoretical calculations demonstrates that the two-photon Raman technique achieves accurate Contact measurements comparable to RF methods. Additionally, it offers advantages in transient measurements and immunity to final-state scattering effects. These findings provide crucial experimental evidence for understanding the microscopic mechanisms of strongly correlated Fermi gases.

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    Xin Bao, Shuxian Yu, Zhijie Zhang, Shujin Deng, Haibin Wu. Measurement of Contact in Strongly Interacting Fermi Gases[J]. Laser & Optoelectronics Progress, 2025, 62(15): 1527001

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    Paper Information

    Category: Quantum Optics

    Received: Apr. 7, 2025

    Accepted: May. 21, 2025

    Published Online: Aug. 11, 2025

    The Author Email: Shujin Deng (sjdeng@lps.ecnu.edu.cn)

    DOI:10.3788/LOP250942

    CSTR:32186.14.LOP250942

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