Direct observation of nonlocal fermion pairing in an attractive Fermi-Hubbard gas

The Hubbard model of attractively interacting fermions provides a paradigmatic setting for fermion pairing. It features a crossover between Bose-Einstein condensation of tightly bound pairs and Bardeen-Cooper-Schrieffer superfluidity of long-range Cooper pairs, and a "pseudo-gap" region wh...

Full description

Saved in:
Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2023-07, Vol.381 (6653), p.82-86
Main Authors: Hartke, Thomas, Oreg, Botond, Turnbaugh, Carter, Jia, Ningyuan, Zwierlein, Martin
Format: Article
Language:English
Subjects:
Fermions
Lattice sites
Optical lattices
Ultracold atoms
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The Hubbard model of attractively interacting fermions provides a paradigmatic setting for fermion pairing. It features a crossover between Bose-Einstein condensation of tightly bound pairs and Bardeen-Cooper-Schrieffer superfluidity of long-range Cooper pairs, and a "pseudo-gap" region where pairs form above the superfluid critical temperature. We directly observe the nonlocal nature of fermion pairing in a Hubbard lattice gas, using spin- and density-resolved imaging of [Formula: see text]1000 fermionic potassium-40 atoms under a bilayer microscope. Complete fermion pairing is revealed by the vanishing of global spin fluctuations with increasing attraction. In the strongly correlated regime, the fermion pair size is found to be on the order of the average interparticle spacing. Our study informs theories of pseudo-gap behavior in strongly correlated fermion systems.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.ade4245