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arXiv:2207.03407

Observation of low-field Feshbach resonances between $^{161}$Dy and $^{40}$K

Zhu-Xiong Ye, Alberto Canali, Elisa Soave, Marian Kreyer, Yaakov Yudkin, Cornelis Ravensbergen, Emil Kirilov, Rudolf Grimm

Published Jul 7, 2022• 0 citations
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Abstract

We report on the observation of Feshbach resonances at low magnetic field strength (below 10 G) in the Fermi-Fermi mixture of $^{161}$Dy and $^{40}$K. We characterize five resonances by measurements of interspecies thermalization rates and molecular binding energies. As a case of particular interest for applications, we consider a resonance near 7.29 G, which combines accurate magnetic tunability and access to the universal regime of interactions with experimental simplicity. We show that lifetimes of a few 100 ms can be achieved for the optically trapped, resonantly interacting mixture. We also demonstrate the hydrodynamic expansion of the mixture in the strongly interacting regime and the formation of DyK Feshbach molecules. Our work opens up new experimental possibilities in view of mass-imbalanced superfluids and related phenomena.

DOI
10.48550/arxiv.2207.03407

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Observation of low-field Feshbach resonances between 161^{161}161Dy and 40^{40}40K
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The authors report the observation of Feshbach resonances in the Fermi-Fermi mixture of ultracold 161{}^{161}161Dy and 40{}^{40}40K. The authors show experimental evidence that Dy-K offers a Feshbach resonance at 7.29 G with properties that could make the study of resonantly interacting mass-imbalanced Fermi-Fermi mixtures possible. In addition, they demonstrate the formation of DyK Feshbach molecules.
Strongly Interacting Fermi-Fermi Mixture of 161^{161}161Dy and 40^{40}40K
We report on the realization of a Fermi-Fermi mixture of ultracold atoms that combines mass imbalance, tunability, and collisional stability. In an optically trapped sample of 161^{161}161Dy and 40^{40}40K, we identify a broad Feshbach resonance centered at a magnetic field of 218 \,G. In the strongly interacting regime, we demonstrate hydrodynamic behavior in the expansion after release from the trap. Lifetime studies on resonance show that the fermionic nature of the system suppresses inelastic few-body processes by several orders of magnitude. The resonant mixture opens up intriguing perspectives for studies on novel states of strongly correlated fermions with mass imbalance.
We report on the realization of a Fermi-Fermi mixture of ultracold atoms that combines mass imbalance, tunability, and collisional stability. In an optically trapped sample of ^{161}Dy and ^{40}K, we identify a broad Feshbach resonance centered at a magnetic field of 217 G. Hydrodynamic expansion profiles in the resonant interaction regime reveal a bimodal behavior resulting from mass imbalance. Lifetime studies on resonance show a suppression of inelastic few-body processes by orders of magnitude, which we interpret as a consequence of the fermionic nature of our system. The resonant mixture opens up intriguing perspectives for studies on novel states of strongly correlated fermions with mass imbalance.
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We report on the observation of Feshbach resonances in ultracold $^{6}\mathrm{Li}\text{\ensuremath{-}}^{164}\mathrm{Dy}$ mixtures, where 6Li^{6}\mathrm{Li}6Li atoms are respectively prepared in their three lowest spin states and 164Dy^{164}\mathrm{Dy}164Dy atoms are prepared in their lowest-energy state. We observe 21 interspecies scattering resonances over a magnetic-field range from 0 to 702 G using atom loss spectroscopy, three of which exhibit relatively broad widths. These broad resonances provide precise control over the interspecies interaction strength, enabling the study of strongly interacting effects in $^{6}\mathrm{Li}\text{\ensuremath{-}}^{164}\mathrm{Dy}$ mixtures. Additionally, we observe a well-isolated interspecies resonance at 700.1 G, offering a unique platform to explore novel impurity physics, where heavy dipolar 164Dy^{164}\mathrm{Dy}164Dy atoms are immersed in a strongly interacting Fermi superfluid of 6Li^{6}\mathrm{Li}6Li atoms.
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