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

We study the collective spin response and spin diffusion of an ultracold lithium Fermi gas artificially engineered in a fully ferromagnetic state, obtained by spatially segregating oppositely-oriented spins into two adjacent reservoirs. In this way, we show that strong repulsive interactions are sufficient to temporarily stabilize ferromagnetic correlations in a Fermi mixture. In particular, we reveal a substantial increase of the magnetic susceptibility of the gas while approaching the critical value of interaction. Correspondingly, we show that above the critical interaction a spin up-down domain wall can persist for a finite time, indicating the metastability of the ferromagnetic state. Such findings point to Stoner-like ferromagnetic instability driven only by short-range repulsion, and are consistent with our recent study of a repulsive Fermi liquid of polarons in strongly polarized Fermi gases.

G. Valtolina, et al.,
Exploring the ferromagnetic behaviour of a repulsive Fermi gas through spin dynamics
Nat. Phys. 13, 704 (2017)

We are pleased to announce the workshop of the EU project QUIC (Quantum Simulations of Insulators and Conductors) which will take place at LENS on April, 20th and 21st. The talks will be open and there will be time for lab visits and scientific discussions for everyone interested, not only for the QUIC team members.

A detailed program of event can be found here

Landau was first to suggest that collective excitations of particle ensembles could be treated as if they were particles themselves, with properties like momentum and mass. As such, these excitations are known as quasiparticles, and in contrast to free particles they possess a finite lifetime. In this study, we report on the investigation of a particular type of quasiparticle known as a Fermi polaron. This is a quantum impurity that is immersed in a Fermi sea and strongly interacts with it. In particular, Fermi polarons emerging from impurities repelling the surrounding particles are known as repulsive polarons. We could observe well-defined repulsive polarons even at very strong interactions, with impurities possessing the same mass as the surrounding particles. In such a system the existence of long-lived repulsive polarons was thus far debated. For this, we have spectroscopically probed an ultracold Fermi gas of lithium, where atoms in a specific internal spin state acted the role of the impurities interacting with a bath of atoms in another spin state. Our findings offer exciting prospects for studying many-body states that rely on repulsive interactions.

F. Scazza, et al.,
Repulsive Fermi Polarons in a Resonant Mixture of Ultracold 6Li Atoms
Phys. Rev. Lett. 118, 083602 (2017)

We demonstrate a novel way of synthesizing spin-orbit interactions in ultracold quantum gases, based on a single-photon optical clock transition coupling two long-lived electronic states of two-electron 173Yb atoms. By mapping the electronic states onto effective sites along a synthetic “electronic” dimension, we have engineered fermionic ladders with synthetic magnetic flux in an experimental configuration that has allowed us to achieve uniform fluxes on a lattice with minimal requirements and unprecedented tunability. We have detected the spin-orbit coupling with fiber-link-enhanced clock spectroscopy and directly measured the emergence of chiral edge currents, probing them as a function of the flux. These results open new directions for the investigation of topological states of matter with ultracold atomic gases.

L. F. Livi et al.,
Synthetic Dimensions and Spin-Orbit Coupling with an Optical Clock Transition
Phys. Rev. Lett. 117, 220401 (2016)

Last Tweets

Seminars & Events

18.02.2020
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.
13.02.2020
Seminar by Dr. Dimitrios Trypogeorgos:
Unconventional topology with a Rashba spin-orbit coupled quantum gas,
h. 14.30 Querzoli room, LENS.
09-10.05.2019
Firenze-Trieste workshop:
Two days of talks and scientific discussions with the theory groups of ICTP and SISSA,
ICTP, Trieste.
17-18.01.2019
Firenze-Trieste workshop:
Two days of talks and scientific discussions with the theory groups of ICTP and SISSA,
Aula Querzoli, LENS.
13.12.2018
Quantumgases retreat:
A full-day group meeting to discuss the activity of the different labs,
h. 9.00 Villa il Gioiello, Arcetri.
24.11.2017
Fermi Colloqium by Prof. Wolfgang Ketterle:
New forms of matter with ultracold atoms: superfluids, supersolids and more,
h. 11.30 Querzoli room, LENS.
27.09.2017
Seminar by Prof. Arno Rauschenbeutel:
Chiral Quantum Optics,
h. 11.00 Querzoli room, LENS.
13.06.2017
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.