Quantum gas microscopy of an attractive Fermi-Hubbard system

Debayan Mitra, Peter T. Brown, Elmer Guardado-Sanchez, Stanimir S. Kondov, Trithep Devakul, David A. Huse, Peter Schauß, Waseem S. Bakr

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

The attractive Fermi-Hubbard model is the simplest theoretical model for studying pairing and superconductivity of fermions on a lattice. It exhibits many interesting features including a short-coherence length at intermediate coupling and a pseudogap regime with anomalous properties. Here we study an experimental realization of this model using a two-dimensional (2D) atomic Fermi gas in an optical lattice. Using a new technique for selective imaging of doublons with a quantum gas microscope, we observe chequerboard doublon density correlations in the normal state close to half-filling. With the aid of quantum Monte Carlo simulations, we show that the measured doublon density correlations allow us to put a lower bound on the strength of s-wave pairing correlations in our system. We compare the temperature sensitivity of the doublon density correlations and the paired atom fraction and find the correlations to be a much better thermometer. Accurate thermometry of attractive lattice systems will be essential in the quest for optimizing cooling schemes to reach superfluid phases in future experiments.

Original languageEnglish (US)
Pages (from-to)173-177
Number of pages5
JournalNature Physics
Volume14
Issue number2
DOIs
StatePublished - Feb 1 2018

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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