Fermions with tunable interactions... In the lithium lab we produce ultracold Fermi gases of 6Li to explore out-of-equilibrium dynamics and transport phenomena in strongly correlated fermionic matter. Atoms are confined into light-imprinted potential structures, simulating the motion of electrons in solid state devices. Our main goal is the study of two-dimensional strongly correlated phases, such as superfluidity across the BCS-BEC crossover and its robustness to disorder.

Ferromagnetic behaviour of a repulsive Fermi gas

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)

Li people

Giulia Del Pace
PhD student
Woo Jin Kwon
Postdoctoral fellow
Francesco Scazza
Scientific staff
Matteo Zaccanti
Scientific staff
Massimo Inguscio
Scientific staff
Giacomo Roati
Scientific staff
Former members:
Andrea Amico
Alessia Burchianti
Chiara Fort
Riccardo Panza
Jorge Seman
Pedro Tavares
Giacomo Valtolina

Li contacts

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

Giacomo Roati
(roati@lens.unifi.it)

Li funding

ERC CoG QUFERM2D
EU Quantum Flagship
Qombs (2018-2021)
PRIN 2017 CEnTraL
Progetto Ente Cassa QuSiM2D
H2020-MSCA-IF-2018 VorDIST
H2020-MSCA-IF-2015 SCOUTFermi2D