Physical Review X (Mar 2018)

Band and Correlated Insulators of Cold Fermions in a Mesoscopic Lattice

  • Martin Lebrat,
  • Pjotrs Grišins,
  • Dominik Husmann,
  • Samuel Häusler,
  • Laura Corman,
  • Thierry Giamarchi,
  • Jean-Philippe Brantut,
  • Tilman Esslinger

DOI
https://doi.org/10.1103/PhysRevX.8.011053
Journal volume & issue
Vol. 8, no. 1
p. 011053

Abstract

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We investigate the transport properties of neutral, fermionic atoms passing through a one-dimensional quantum wire containing a mesoscopic lattice. The lattice is realized by projecting individually controlled, thin optical barriers on top of a ballistic conductor. Building an increasingly longer lattice, one site after another, we observe and characterize the emergence of a band insulating phase, demonstrating control over quantum-coherent transport. We explore the influence of atom-atom interactions and show that the insulating state persists as contact interactions are tuned from moderately to strongly attractive. Using bosonization and classical Monte Carlo simulations, we analyze such a model of interacting fermions and find good qualitative agreement with the data. The robustness of the insulating state supports the existence of a Luther-Emery liquid in the one-dimensional wire. Our work realizes a tunable, site-controlled lattice Fermi gas strongly coupled to reservoirs, which is an ideal test bed for nonequilibrium many-body physics.