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!


Welcome Nigel!

It is a great privilege for us to welcome Nigel Cooper, Professor in Theoretical Physics of University of Cambridge. Prof. Cooper will honour us with his presence for one year as a Visiting Professor of the Department of Physics and Astronomy of the University of Florence.
The research interests of Prof. Cooper are focused on the nature and properties of the novel phases of matter that can emerge as a result of quantum mechanical effects in interacting many-particle systems. In particular, he is a world leader in the investigation of the role of topology in the collective properties of ultra-cold atomic gases and of the electronic properties of novel solid state materials. He was awarded the 2007 Maxwell Medal and Prize by the Institute of Physics, a Humboldt Research Award (2013), an EPSRC Established Career Fellowship (2013), a Simons Investigator Award (2017) and the 2019 Lord Rayleigh Prize of the IOP.

We are very grateful to him and looking forward to inspiring discussions and collaborations. We wish him a very pleasant and productive stay at University of Florence and LENS!

Unveiling the effect of interactions in the interference pattern of Bose-Einstein condensates

We have experimentally and theoretically studied how the interactions affect the interference pattern of two expanding 87Rb condensates. Our analysis shows that the condensate phase is modified by the mutual interaction only in the region where the wave packets overlap. This result proves that the general assumption of phase rigidity has to be abandoned for an accurate description of matter-wave interference.

A. Burchianti et al.
Effect of interactions in the interference pattern of Bose-Einstein condensates
Phys. Rev. A 102, 043314 (2020)

Sensitivity bounds of a spatial Bloch-oscillations Atom Interferometer

We study the ultimate bounds on the sensitivity of a Bloch-oscillation atom interferometer where the external force is estimated from the measurement of the on-site atomic density. For external forces such that the energy difference between lattice sites is smaller than the tunneling energy, the atomic wave-function spreads over many lattice sites, increasing the separation between the occupied modes of the lattice and naturally enhancing the sensitivity of the interferometer. To investigate the applicability of this scheme we estimate the effect of uncontrolled fluctuations of the tunneling energy and the finite resolution of the atom detection. Our analysis shows that a horizontal lattice combined with a weak external force allow for high sensitivities. Therefore, this setup is a promising solution for compact devices or for measurements with high spatial resolution.

I. Nałȩcz, et al.,
Sensitivity bounds of a spatial Bloch-oscillation atom interferometer
Phys. Rev. A 102, 033318 (2020)

CriLiN just started! Congratulations Alessio!

Within the CriLiN project, EU-funded through a Marie Skłodowska-Curie action, Alessio will develop a novel type of atomic quantum simulator with long-range, multi-body interactions.

Supercurrents disclose the order parameter in strongly interacting Fermi gases

When two superconductors are coupled with one another through an insulating junction, a so-called Josephson supercurrent may flow without creating any potential difference, sustained merely by a phase difference between the superconducting wave functions. We have observed the charge-neutral analogue of this phenomenon using an ultracold gas of strongly interacting fermionic atoms, revealing the quintessential sinusoidal relationship between the supercurrent and the superfluid phase. Our experiments demonstrate the profound connection between the supercurrent magnitude and the nature of superfluid states, which has allowed us to quantify the condensate density across the BCS-BEC crossover of ultracold Fermi gases, playing the role of the superfluid order parameter.

W. J. Kwon et al.
Strongly correlated superfluid order parameters from dc Josephson supercurrents
Science 369, 84 (2020)

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