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arXiv:2203.12965 · Physical Review Letters

Exploring Ultracold Collisions in Li6−Cr53 Fermi Mixtures: Feshbach Resonances and Scattering Properties of a Novel Alkali-Transition Metal System

A. Ciamei, Stefano Finelli, A. Trenkwalder, M. Inguscio, Andrea Simoni, Matteo Zaccanti

Published Aug 26, 2022• 26 citations
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Abstract

We investigate ultracold collisions in a novel mixture of ^{6}Li and ^{53}Cr fermionic atoms, discovering more than 50 interspecies Feshbach resonances via loss spectroscopy. Building a full coupled-channel model, we unambiguously characterize the ^{6}Li-^{53}Cr scattering properties and yield predictions for other isotopic pairs. In particular, we identify various Feshbach resonances that enable the controlled tuning of elastic s- and p-wave ^{6}Li-^{53}Cr interactions. Our studies thus make lithium-chromium mixtures emerge as optimally suited platforms for the experimental search of elusive few- and many-body regimes of highly correlated fermionic matter, and for the realization of a new class of ultracold polar molecules possessing both electric and magnetic dipole moments.

DOI
10.1103/physrevlett.129.093402

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We investigate ultracold collisions in a novel mixture of ^{6}Li and ^{53}Cr fermionic atoms, discovering more than 50 interspecies Feshbach resonances via loss spectroscopy. Building a full coupled-channel model, we unambiguously characterize the ^{6}Li-^{53}Cr scattering properties and yield predictions for other isotopic pairs. In particular, we identify various Feshbach resonances that enable the controlled tuning of elastic s- and p-wave ^{6}Li-^{53}Cr interactions. Our studies thus make lithium-chromium mixtures emerge as optimally suited platforms for the experimental search of elusive few- and many-body regimes of highly correlated fermionic matter, and for the realization of a new class of ultracold polar molecules possessing both electric and magnetic dipole moments.
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We have observed 26 interspecies Feshbach resonances at fields up to 2050 G in ultracold 6Li+23Na{}^{6}\text{Li}+{}^{23}\text{Na}6Li+23Na mixtures for different spin-state combinations. Applying the asymptotic bound-state model to assign the resonances, we found that most resonances have ddd-wave character. This analysis serves as guidance for a coupled-channel calculation, which uses modified interaction potentials to describe the positions of the Feshbach resonances well within the experimental uncertainty and to calculate their widths. The scattering length derived from the improved interaction potentials is experimentally confirmed and deviates from previously reported values in sign and magnitude. We give prospects for 7Li+23Na{}^{7}\text{Li}+{}^{23}\text{Na}7Li+23Na and predict broad Feshbach resonances suitable for tuning.