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

Welcome to the website of the Ultracold Quantum Gases group at the European Laboratory for Nonlinear Spectroscopy (LENS) and Department of Physics and Astronomy of the University of Florence (Italy). 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

Laser cooling based on dark states, i.e. states decoupled from light, has proven to be effective to increase the phasespace density of cold trapped atoms. Dark-states cooling requires open atomic transitions, in contrast to the ordinary laser cooling used for example in magneto-optical traps (MOTs), which operate on closed atomic transitions. For alkali atoms, dark-states cooling is therefore commonly operated on the D1 transition nS1/2 → nP1/2. We show that, for 87Rb, thanks to the large hyperfine structure separations the use of this transition is not strictly necessary and that “quasi-dark state” cooling is efficient also on the D2 line, 5S1/2 → 5P1/2. We report temperatures as low as (4.0 ± 0.3) μK and an increase of almost an order of magnitude in the phase space density with respect to ordinary laser sub-Doppler cooling.

S. Rosi, et al.
Λ -enhanced grey molasses on the D2 transition of Rubidium-87 atoms
Sci. Rep. 8, 1301 (2018)

We study the emergence of dissipation in an atomic Josephson junction between weakly coupled superfluid Fermi gases. We find that vortex-induced phase slippage is the dominant microscopic source of dissipation across the BEC–BCS crossover. We explore different dynamical regimes by tuning the bias chemical potential between the two superfluid reservoirs. For small excitations, we observe dissipation and phase coherence to coexist, with a resistive current followed by well-defined Josephson oscillations. We link the junction transport properties to the phase-slippage mechanism, finding that vortex nucleation is primarily responsible for the observed trends of the conductance and critical current. For large excitations, we observe the irreversible loss of coherence between the two superfluids, and transport cannot be described only within an uncorrelated phase-slip picture. Our findings open new directions for investigating the interplay between dissipative and superfluid transport in strongly correlated Fermi systems, and general concepts in out-of-equilibrium quantum systems.

A. Burchianti, et al.,
Connecting Dissipation and Phase Slips in a Josephson Junction between Fermionic Superfluids
Phys. Rev. Lett. 120, 025302 (2018)

We observed the transition to BEC for 162Dy atoms!
Our dipolar BECs are made up at the moment by up to 3⨯104 atoms. Atoms from the MOT are transferred into an in-vacuum optical resonator where we perform a first evaporation down to a few μK. Afterwards, we load the atoms in a crossed optical trap and condensation temperature is reached by evaporation ramps. The atomic dipoles are aligned along the vertical direction by an uniform magnetic field of a few Gauss and the vertical trapping frequency is higher than the horizontal ones to prevent dipolar collapse. The transition temperature for our trapping potential is below 100 nK.

We achieved a 87Rb condensate of 4⨯105 atoms in the F=2, mF=2 state. We use a hybrid trap consisting of a single focused laser beam at 1064nm (dimple) in the horizontal direction and a quadrupole magnetic field. The dimple is vertically shifted with respect to the quadrupole center to avoid Majorana spin-flips. A first evaporation ramp with a microwave driving the (2,2) to (1,1) transition, is followed by an optical evaporation.

Last Tweets

Seminars & Events

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.
23.11.2017
Prof. Wolfgang Ketterle will give a lecture for students and everyone else interested on the topic:
Superfluid Bose and Fermi gases,
h. 15.00 Room 25, Blocco Aule.
27.09.2017
Seminar by Prof. Arno Rauschenbeutel:
Chiral Quantum Optics,
h. 11.00 Querzoli room, LENS.
19.07.2017
Seminar by Prof. Maarten Hoogerland:
Atomtronics and cavity QED experiments in Auckland,
h. 11.30 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.
20 & 21.04.2017
QUIC Project Meeting
See detailed program
Querzoli room, LENS.
10.04.2017
Seminar by Prof. Nick Proukakis:
Non-Equilibrium Dynamics in Quantum Gases,
h. 11.00 Querzoli room, LENS.
23.02.2017
Seminar by Prof. David Clément:
Momentum-resolved investigation of the condensate depletion in interacting Bose gases,
h. 15.00 Querzoli room, LENS.
22.02.2017
Seminar by Dr. Carmine Ortix:
Symmetry-protected topological insulators in one-dimension,
h. 12.00 Querzoli room, LENS.