Mass imbalanced fermions are great! In the CrLi lab we produce novel ultracold mixtures composed by Lithium and Chromium fermionic atoms. At the Cr-Li mass ratio exotic trimer states exist, which in turn will allow the first resonant control of elastic three-body interactions. This opens new perspectives for the study of elusive superfluid and magnetic phases with ultracold fermions.

Max Schemmer has joined the LiCr team as Senior researcher.
Max has previously worked on 1-D quantum gases during his PhD under supervision of Isabelle Bouchoule (Laboratoire Charles Fabry, Palaiseau, France), and has has later worked as Marie-Curie fellow on quantum optics with cold atom-optical nanofiber hybrid platforms in the group of Arno Rauschenbeutel (Humboldt Universität zu Berlin).

Viel Glück Max!

Alessio Ciamei and Max Schemmer have both won the "Young Researcher" grant funded by the Italian Ministry of University and Research (MUR) with 300k€, each for the next 3 years.
A. C. will realize an ultracold gas of Polar Paramagnetic Molecules (PoPaMol) of LiCr and exploit this new class of molecules to perform ultracold chemistry studies and high precision spectroscopy.
M. S. plans to reveal Majorana states in Li-Cr p-wave superfluids, paving the way for topological quantum computing (MajorSuperQ).

Buona fortuna a entrambi!

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 2x105 6Li and 105 53Cr atoms with T/TF 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)

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).

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!

Cr/Li people

Beatrice Restivo
Master Student
Antonio Cosco
Master Student
Stefano Finelli
PhD Student
Maximilian Schemmer
Research Fellow
Alessio Ciamei
Research Fellow
Andreas Trenkwalder
Scientific Staff
Massimo Inguscio
Scientific Staff
Matteo Zaccanti
Scientific Staff
Former members:
Michael Jag
Elettra Neri
Michele Pini
Cristiano Simonelli

Cr/Li contacts

For further information, request of material, job opportunities, please contact:

Matteo Zaccanti
(zaccanti@lens.unifi.it)

Cr/Li funding

ERC StG PoLiChroM
MIUR FARE P-HeLiCS
Young Researchers-MUR
H2020-MSCA-IF-2019 CriLiN