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!


In this work we experimentally demonstrate that the undo of an operation is possible also in quantum regimes. The last performed operation can be time-reversed via the undo command so as to perfectly restore a condition in which any new operation can be applied by an external user. We exploit the optimal control algorithm based on the dressed chopped random basis method, to perform several time-reversal transformations. We implement this algorithm by applying different levels of complexity, in terms of control, in order to manipulate the forward and backward internal state dynamics of a 87Rb Bose–Einstein condensate within an atom chip. As well as providing a thermodynamic interpretation of our results, in this paper we demonstrate that the quantum undo command can be performed also by time-reversing an operation in a generic instant of the past. The concept of quantum undo can be thus generalized. An external user, indeed, will be able to restore not only the last but also any past step of his complex computational routine. We are confident that our successful results could be applied in the next future on a real gate-based quantum computer.

I. Mastroserio, et al.,
Experimental Realization of Optimal Time-Reversal on an Atom Chip for Quantum Undo Operations
Adv. Quantum Technol. 2022, 2200057 (2022)

Paper appeared as back cover on Advanced Quantum Technologies 12/2022.

A large repulsion between particles in a quantum system can lead to their localization, an effect responsible for the Mott insulator phases in strongly correlated materials. In a system with multiple orbitals, an orbital-selective Mott insulator can form, where electrons in some orbitals are predicted to localize while others remain itinerant. Here we demonstrate a more general version of this phenomenon by observing flavour-selective localization in an atom-based quantum simulator. Our experiment realizes Fermi–Hubbard models with an SU(3) symmetry that can be broken using a tunable coupling between flavours. We observe an enhancement of the localization associated with a selective Mott transition and the emergence of flavour-dependent correlations. Our realization of flavour-selective Mott physics demonstrates the potential of cold atoms to simulate interacting multicomponent materials such as superconductors and topological insulators.

D. Tusi, et al.
Flavour-selective localization in interacting lattice fermions
Nat. Phys. 18, 1201 (2022)

During the national congress of the Società Italiana di Fisica (SIF), held in Milan from the 12th to the 16th of September, the prize for young graduates in physics, entitled to Giuliano Toraldo di Francia, has been awarded to Giulio Biagioni, PhD student of the Department of Physics and Astronomy of the University of Florence working in the Dy Lab. Giulio's PhD project is focused on the study of the supersolid phase of matter in a dipolar quantum gas.

See also the SIF congress webpage

Our preprint on orientational melting of ion crystals is now on the arXiv! We studied the peculiar melting of our 2D crystals: the loss of crystallization along the angular direction and its dependence on particle number and impurities reveals the mesoscopic character of the observed transition. Our work paves the way to studies of thermodynamics of small systems and of quantum rotors. Read more on the arxiv!

L. Duca, et al.
Orientational melting in a mesoscopic system of charged particles
arXiv 2209.00395 (2022)

Together with Giacomo Bighin and Tommaso Macrì, we studied the problem of a mobile impurity immersed in a bosonic mixture. We focused on the experimental relevant case of a 41K−87Rb mixture, prepared in its ground-state, with the impurity consisting of a few 41K atoms in the second-lowest hyperfine state. We provided a compressive picture of the impurity across the mixture phase diagram. In the droplet phase, under realistic experimental conditions, we found exotic bound-states where the impurity localized either at the center or at the droplet surface. Our findings provide new insights for the study and detection of Bose polarons in collisionally stable and long-lived Bose mixtures such as the 41K-87Rb one.

G. Bighin et al.
Impurity in a heteronuclear two-component Bose mixture
Phys. Rev. A 106, 023301 (2022)

Seminars & Events

InnFi Joint Meeting on Ultracold Atoms:
Experimental and theoretical groups from Innsbruck (Austria) and Florence (Italy) research areas will present their activities and discuss collaborations. Click here for more info.