Pushing the limits of atom interferometry...The system we want to realize is a Mach-Zender spatial interferometer operating with trapped Bose-Einstein condensates (BECs). Phase diffusion caused by interatomic collisions are suppressed implementing BECs with tunable interactions in ultra-stable optical potentials. Entangled states can be used to improve the sensitivity of the sensor beyond the standard quantum limit to ideally reach the ultimate, Heisenberg, limit set by quantum mechanics. Our project aims at developing a sensor with unprecedented spatial resolution able to compete with, and eventually overcome, state-of-the-art interferometers with cold (non condensed) atomic waves.

Self-bound quantum droplets of atomic mixtures observed

We report on the observation of quantum liquid droplets in a bosonic mixture. While ultracold atomic systems are commonly found in a gas phase, recent theoretical and experimental results have surpringly pointed out that under special circumstances condensed atoms can form self-bound liquid-like droplets. At the origin of this new phase is the coexistence of repulsive and attractive forces that perfectly balance to generate the self-binding mechanism. The two competing energies are provided by the mean-field interaction and the first beyond mean-field correction, the so-called Lee-Huang-Yang term. We observe the existence of such self-bound ensembles in a bosonic mixture of K-39 atoms and we characterize their equilibrium properties. Quantum droplets are predicted to be macroscopic zero-temperature objects, due to their peculiar energy spectrum, where no discrete modes are expected below the particle emission threshold. The observation reported in this work certainly opens the way to further studies of the exotic properties of this new phase, which also constitutes the only known quantum liquid together with helium nanodroplets.

G. Semeghini, et al.,
Self-Bound Quantum Droplets of Atomic Mixtures in Free Space
Phys. Rev. Lett. 120, 235301 (2018)

K2 people

Louise Wolswijk
Master student
Giovanni Giusti
Master student
Leonardo Masi
PhD student
Giovanni Ferioli
PhD student
Giulia Semeghini
Research fellow
Giovanni Modugno
Permanent researcher
Massimo Inguscio
Permanent researcher
Marco Fattori
Permanent researcher
Former members:
Simon Coop
Manuele Landini
Sanjukta Roy
Giacomo Spagnolli
Andreas Trenkwalder

K2 contacts

For further information, request of material, job opportunities, please contact:

Marco Fattori
(fattori@lens.unifi.it)

K2 funding

ERC StG AISENS
EU FP7 QIBEC
FIRB Futuro in Ricerca
2010 RBFR08H058_001
INFN Progetto Premiale
Atom Interferometer