Taming, slowing and trapping atoms with light
Cold is quantum, Quantum is cool!
We shape quantum matter
Multicolored lasers for a variety of atoms
Keeping our eyes on the quantum world
Join our ultracool group!
High technology for great science

Welcome to the website of the Ultracold Quantum Gases group at the European Laboratory for Nonlinear Spectroscopy (LENS), the Department of Physics and Astronomy of the University of Florence (Italy) and the Institute of Optics of the Italian National Research Council (CNR - INO). In our labs we use lasers and magnetic fields to produce the lowest temperatures of the Universe, just a few billionths of a degree above absolute zero...

At these temperatures, atoms stop moving and we can control them for a variety of different fundamental studies and applications. We can force atoms to arrange according to a periodic structure and simulate the behavior of crystalline solids and new materials. We can use the atoms as ultra-high accurate sensors to probe forces with the power of quantum mechanics. We can study how quantum particles combine together under the action of strong interactions and how superfluidity develops. We can use these ultracold atoms to process information and develop new quantum technologies.

Dress warmly and... follow us for this ultracold journey!


When two superconductors are coupled with one another through an insulating junction, a so-called Josephson supercurrent may flow without creating any potential difference, sustained merely by a phase difference between the superconducting wave functions. We have observed the charge-neutral analogue of this phenomenon using an ultracold gas of strongly interacting fermionic atoms, revealing the quintessential sinusoidal relationship between the supercurrent and the superfluid phase. Our experiments demonstrate the profound connection between the supercurrent magnitude and the nature of superfluid states, which has allowed us to quantify the condensate density across the BCS-BEC crossover of ultracold Fermi gases, playing the role of the superfluid order parameter.

W. J. Kwon et al.
Strongly correlated superfluid order parameters from dc Josephson supercurrents
Science 369, 84 (2020)

One of the main limitations in state-of-the-art atom-ion experiments is represented by the micromotion component of the ions’ dynamics in a Paul trap that prevents atom-ion mixtures from undergoing a coherent evolution. Overcoming this problem requires a completely new approach to ion trapping. Our solution is a novel micromotion-free electro-optical trap based on the combination of an optical and a static electrostatic field. In this paper, we describe the geometry and the assembly of an electro-optical trap explicitly designed for experiments with atom-ion mixtures, in our case a mixture of Barium ions and Lithium atoms. We also report the results of the numerical simulations performed on the electric and thermal behavior of the trap, providing fundamental information for establishing the trapping potential and the stability region.

E. Perego, et al.
Electro-Optical Ion Trap for Experiments with Atom-Ion Quantum Hybrid Systems
Appl. Sci. 2020, 10, 2222 (2020)

We have projected micron-scale light potentials onto quasi-2D degenerate Fermi gases of lithium-6. A single atomic layer is created by vertically compressing a 3D atomic cloud into a highly anisotropic blue-detuned TEM01-mode optical trap, with very weak in-layer confinement. A digital micromirror device (DMD) is then used here to mold the skyline of Florence in a unitary Fermi gas. The sample is imaged with micron resolution by the same high-resolution objective used for focusing the sculpted light potential. These new capabilities enable exciting investigations of fermionic quantum transport and out-of-equilibrium dynamics in a large variety of paradigmatic scenarios.

We theoretically investigate the onset of dissipation in the Josephson dynamics between two atomic Fermi superfluids. We demonstrate that resistive currents are directly connected with nucleations of vortex rings and their propagation into the superfluid bulk. We compare the simulations with our recent experimental results, finding excellent agreement. This work has been carried out in collaboration with the theory group of the University of Newcastle, led by Prof. Proukakis and it will be valuable for advancing our comprehension of the complex superfluid transport in emerging atomtronic devices.

K. Xhani et al.
Critical Transport and Vortex Dynamics in a Thin Atomic Josephson Junction
Phys. Rev. Lett. 124, 045301 (2020)

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Seminars & Events

Seminar by Prof. Carlos Sa de Melo:
Ultra-cold Fermi Gases with Three and Four Internal States: The Evolution from BCS to BEC Superfluidity in Multiband Systems ,
h. 12.00 Querzoli room, LENS.
Seminar by Dr. Dimitrios Trypogeorgos:
Unconventional topology with a Rashba spin-orbit coupled quantum gas,
h. 14.30 Querzoli room, LENS.
Firenze-Trieste workshop:
Two days of talks and scientific discussions with the theory groups of ICTP and SISSA,
ICTP, Trieste.
Firenze-Trieste workshop:
Two days of talks and scientific discussions with the theory groups of ICTP and SISSA,
Aula Querzoli, LENS.
Quantumgases retreat:
A full-day group meeting to discuss the activity of the different labs,
h. 9.00 Villa il Gioiello, Arcetri.
Fermi Colloqium by Prof. Wolfgang Ketterle:
New forms of matter with ultracold atoms: superfluids, supersolids and more,
h. 11.30 Querzoli room, LENS.
Seminar by Prof. Arno Rauschenbeutel:
Chiral Quantum Optics,
h. 11.00 Querzoli room, LENS.
The LENS QuantumGases group is glad to welcome in Florence Prof. Randall Hulet from Rice University. Prof. Hulet will be our guest for one month until mid July.