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!

LAST NEWS

First italian trapped ions!

Happy to announce the first ion crystals of Ba+ observed in our unconventional ion trap. Congrats to all the people that worked on the project!

A new sideband cooling scheme for efficient cooling in challenging trapping potentials

Cooling neutral atoms in optical traps can be a difficult task under some experimental conditions, like when optical trapping potentials are state-dependent. We report on a theoretical study showing that cooling can be achieved even if the internal states of the atoms experience different potential depths as long as a well-tailored frequency sweep is applied to the cooling laser. We develop a master rate equation and a Monte Carlo simulation for atoms of Li and Yb trapped in optical lattices and tweezers and we find that the average occupation number of the vibrational levels is drastically reduced under feasible experimental conditions. Our findings provide an alternative cooling scheme that can be applied in principle to any particle that is optically trappable, e.g. atoms, molecules or ions, and can provide a faster route to cooling atoms to condensation or degeneracy.

F. Berto, et al.
Prospects for single-photon sideband cooling of optically trapped neutral atoms
Phys. Rev. Research 3, 043106 (2021)

A novel lattice with arbitrary large spatial periodicity has been invented

We report the experimental realization of a new kind of optical lattice for ultra-cold atoms where arbitrarily large separation between the sites can be achieved without renouncing to the stability of ordinary lattices. Two collinear lasers, with slightly different commensurate wavelengths and retrorefected on a mirror, generate a superlattice potential with a periodic \beat-note" profile where the regions with large amplitude modulation provide the effective potential minima for the atoms. To prove the analogy with a standard large spacing optical lattice we study Bloch oscillations of a Bose Einstein condensate with negligible interactions in the presence of a small force. The observed dynamics between sites separated by ten microns for times exceeding one second proves the high stability of the potential. This novel lattice is the ideal candidate for the coherent manipulation of atomic samples at large spatial separations and might find direct application in atom-based technologies like trapped atom interferometers and quantum simulators.

L. Masi, et al.,
Spatial Bloch Oscillations of a Quantum Gas in a “Beat-Note” Superlattice
Phys. Rev. Lett. 127, 020601 (2021)

A new design of a Littrow-type ECDL has been patented

We report on our patented Littrow-type external cavity diode laser (ECDL) in which the coarse wavelength adjustment obtained via the rotation of a diffraction grating is decoupled from the fine tuning of the cavity modes done with changes in the external cavity length. This design improves the robustness of the ECDL emission against misalignment and hysteresis, even for the case of long external cavity lasers typically employed in optical clock experiments.

L. Duca, et al.
Design of a Littrow-type diode laser with independent control of cavity length and grating rotation
Opt. Lett. 46, 2840 (2021)

Spotting superfluidity in a supersolid from non-classical rotational inertia

A key manifestation of superfluidity in liquids and gases is a reduction of the moment of inertia under slow rotations. Non-classical rotational effects have been searched for a long time also for the elusive supersolid phase of matter, in which superfluidity coexists with a lattice structure. Here we show that the recently discovered supersolid phase in dipolar quantum gases features a reduced moment of inertia. We study a peculiar rotational oscillation mode in a harmonic potential, the scissors mode, already employed for superfluids. From the measured moment of inertia, we derive a superfluid fraction in analogy with the original definition by A. J. Leggett. The superfluid fraction is different from zero and of order of unity, providing direct evidence of the superfluid nature of the dipolar supersolid. A qualitative comparison with the original theoretical model supports the observation of a large superfluid fraction close to the transition from the Bose-Einstein condensate (BEC) and the supersolid.

L. Tanzi, et al.
Evidence of superfluidity in a dipolar supersolid from non-classical rotational inertia
Science 371, 1162 (2021)

We use cookies

We use cookies on our website. Some of them are essential for the operation of the site, while others help us to improve this site and the user experience (tracking cookies). You can decide for yourself whether you want to allow cookies or not. Please note that if you reject them, you may not be able to use all the functionalities of the site.