We have reached simultaneous quantum degeneracy for fermionic Li and Cr atoms for the first time. In this work, we explain our all-optical strategy to realize large samples of more than 2x10^{5 6}Li and 10^{5 53}Cr atoms with T/T_F as low as 0.25 in less than 13 s. Moreover, by use of a crossed bichromatic optical dipole trap, we are able to control the relative density and degree of degeneracy of the mixture components. This novel mass-imbalanced Fermi mixture, which we already proved to possess suitable Feshbach resonances in a previous work [Phys. Rev. Lett. 129, 093402 (2022)], opens the way to the observation of novel exotic few- and many-body phenomena, as well as the creation of ultracold polar paramagnetic LiCr molecules. Finally, our experimental methods can be exploited to realize large Fermi gases or homonuclear spin-mixtures of ⁵³Cr, which will enable us to investigate the effects of weak dipolar interactions on BEC-BCS crossover physics.

Our results have been recently published in Physical Review A:

A. Ciamei et al.
Double-degenerate Fermi mixtures of ⁶Li and ⁵³Cr atoms
Phys. Rev. A 106, 053318 (2022)

Our preprint on ultracold collisions in 6Li-53Cr mixtures is now on the arXiv! We have performed extensive Feshbach spectroscopy of various spin combinations revealing more than 50 resonances between 0 and 1500 G. By means of a full coupled-channel model, we have unambiguously assigned a complete set of quantum numbers to each resonance and derived a thorough characterization of the scattering properties of our system. This has enabled us to identify several resonances suitable for future few-body and many-body studies of mass-imbalanced Fermi mixtures. What is more, our work paves the way to the production of a new class of ultracold molecules possessing both electric and magnetic dipole moments.

Stay tuned!

A. Ciamei et al.
Exploring ultracold collisions in ⁶Li-⁵³Cr Fermi mixtures: Feshbach resonances and scattering properties of a novel alkali-transition metal system
arXiv:2203.12965 (2022)

Within the CriLiN project, EU-funded through a Marie Skłodowska-Curie action, Alessio will develop a novel type of atomic quantum simulator with long-range, multi-body interactions.

In the middle of the hot Tuscan summer, we could bring to quantum degeneracy large samples of ⁶Li atoms in our setup. With the same all-optical strategies already developed in the LiLab, we can achieve crossover superfluids, as well as highly degenerate Fermi gases, of up to 1 million atoms. (In the image, the hydrodynamic expansion of a crossover superfluid of about 700000 pairs).

We brought into the cold regime the first chromium-lithium fermionic mixture worldwide. within a 5 sec. duty cycle, we produce samples of about 4 million chromium and 300 million lithium atoms at a few hundreds of microKelvin. Our work just got published in Phys. Rev. A.

E. Neri, et al.,
Realization of a cold mixture of fermionic chromium and lithium atoms
Phys. Rev. A 101, 063602 (2020)

Together with Wilhelm Zwerger, we developed a simple analytic model to quantitatively describe the Josephson tunneling between two Fermi superfluids along the entire BCS-BEC crossover. Our work just got published in Phys. Rev. A.

M. Zaccanti, W. Zwerger,
Critical Josephson current in BCS-BEC–crossover superfluids
Phys. Rev. A 100, 063601 (2019)

We devised a simple, totally passive scheme that enables to realize an inexpensive optical trapping apparatus free from thermal lensing effects. Our work just got published in Optics Express.

C. Simonelli et al.,
Realization of a high power optical trapping setup free from thermal lensing effects
Opt. Express 27, 27215 (2019)

We have finalized the construction of the experimental setup, and we're now able to produce the first Lithium-Chromium MOT worldwide! Fun has just begun!

We have completed the design of the dual-species vacuum setup of the experiment and its construction will begin very soon. Stay tuned for updates!

We have recently developed a home-made and unexpensive high power laser source @425nm: up to 800mW of blue light for laser cooling of Chromium!

Matteo Zaccanti has been awarded with an ERC Starting Grant! The title of the project is "PoLiChroM: Superfluidity and ferromagnetism of unequal mass fermions with 2- and 3-body resonant interactions” (proposal #637738). Congratulations!