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) 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!


Ultracold molecules have experienced increasing attention in recent years. Compared to ultracold atoms, they possess several unique properties that make them perfect candidates for the implementation of new quantum-technological applications in several fields, from quantum simulation to quantum sensing and metrology. In particular, ultracold molecules of two-electron atoms (such as strontium or ytterbium) also inherit the peculiar properties of these atomic species, above all, the possibility to access metastable electronic states via direct excitation on optical clock transitions with ultimate sensitivity and accuracy. We report on the production and coherent manipulation of molecular bound states of two fermionic 173Yb atoms in different electronic (orbital) states 1S0 and eP0 in the proximity of a scattering resonance involving atoms in different spin and electronic states, called orbital Feshbach resonance. We demonstrate that orbital molecules can be coherently photoassociated starting from a gas of ground-state atoms in a three-dimensional optical lattice by observing several photoassociation and photodissociation cycles. We also show the possibility to coherently control the molecular internal state by using Raman-assisted transfer to swap the nuclear spin of one of the atoms forming the molecule, thus demonstrating a powerful manipulation and detection tool of these molecular bound states. Finally, by exploiting this peculiar detection technique we provide the first information on the lifetime of the molecular states in a many-body setting, paving the way towards future investigations of strongly interacting Fermi gases in a still unexplored regime.

G. Cappellini, et al.
Coherent Manipulation of Orbital Feshbach Molecules of Two-Electron Atoms
Phys. Rev. X 9, 011028 (2019)

Analogously to a beating heart, the electrodes of an ion trap need to receive synchronous RF electric signals with a precise frequency and phase in order to function properly. We developed a compact RF drive for the electrodes of our ion trap composed of interdependent RLC circuits resonating at iso-frequency, iso-amplitude and with proper phase opposition. The circuit provides an amplification factor of 200 and it allows ions' micromotion correction via feedback loops.

A. Detti, et al.
A compact radiofrequency drive based on interdependent resonant circuits for precise control of ion traps
Rev. Sci. Instrum. 90, 023201 (2019)

Strong interactions among fermionic particles in condensed matter are known to foster rich phase diagrams, where distinct microscopic mechanisms compete with one another. In this work, we reveal the emergence of two competing instabilities in a paradigmatic model system, i.e., a Fermi gas of ultracold atoms. While it has been established that a cold gas of atoms subject to strong interactions is unstable towards forming pairs of oppositely oriented spins, a long-standing issue is whether strong repulsion can trigger fermions to build up correlations and develop ferromagnetic order. Here, we probe the out-of-equilibrium dynamics of a repulsive Fermi gas with unprecedented time resolution, exploiting a pump-probe spectroscopic technique akin to the ultrafast spectroscopy used in the solid state. In this way, we witness the real-time growth of spin anti-correlations in the gas driven only by repulsive interactions. Their interplay with the tendency of fermions to pair up is found to persist over long time scales, giving rise to a novel, emulsion-like metastable state unforeseen thus far. These findings represent an important testbed for current and future theories, while they also afford exciting perspectives for accessing elusive regimes of fermionic superfluidity.

A. Amico, F. Scazza, G. Valtolina, P. E. S. Tavares, W. Ketterle, M. Inguscio, G. Roati, and M. Zaccanti
Time-Resolved Observation of Competing Attractive and Repulsive Short-Range Correlations in Strongly Interacting Fermi Gases
Phys. Rev. Lett. 121, 253602 (2018)

See also the Physics Viewpoint by L. LeBlanc:

L. LeBlanc
The Quest to Make a Ferromagnet with Cold Atoms
Physics 11, 131 (2018)

We report on the production of a 41K−87Rb dual-species Bose-Einstein condensate in a hybrid trap, consisting of a magnetic quadrupole and an optical dipole potential. After loading both atomic species in the trap, we cool down 87Rb first by magnetic and then by optical evaporation, while 41K is sympathetically cooled by elastic collisions with 87Rb. We eventually produce two-component condensates with more than 105 atoms and tunable species population imbalance. We observe the immiscibility of the quantum mixture by measuring the density profile of each species after releasing them from the trap.

A. Burchianti, et al.
Dual-species Bose-Einstein condensate of 41K and 87Rb in a hybrid trap
Phys. Rev. A 98, 063616 (2018)

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Seminars & Events

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.
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.
Seminar by Prof. Arno Rauschenbeutel:
Chiral Quantum Optics,
h. 11.00 Querzoli room, LENS.
Seminar by Prof. Maarten Hoogerland:
Atomtronics and cavity QED experiments in Auckland,
h. 11.30 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.
20 & 21.04.2017
QUIC Project Meeting
See detailed program
Querzoli room, LENS.
Seminar by Prof. Nick Proukakis:
Non-Equilibrium Dynamics in Quantum Gases,
h. 11.00 Querzoli room, LENS.
Seminar by Prof. David Clément:
Momentum-resolved investigation of the condensate depletion in interacting Bose gases,
h. 15.00 Querzoli room, LENS.
Seminar by Dr. Carmine Ortix:
Symmetry-protected topological insulators in one-dimension,
h. 12.00 Querzoli room, LENS.