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arXiv · 1705.02039

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
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Abstract

The attractive Fermi-Hubbard model is the simplest theoretical model for studying pairing and superconductivity of fermions on a lattice. Although its s-wave pairing symmetry excludes it as a microscopic model for high-temperature superconductivity, it exhibits much of the relevant phenomenology, 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. Our site-resolved measurements on the normal state reveal checkerboard charge-density-wave correlations close to half-filling. A "hidden" SU(2) pseudo-spin symmetry of the Hubbard model at half-filling guarantees superfluid correlations in our system, the first evidence for such correlations in a single-band Hubbard system of ultracold fermions. Compared to the paired atom fraction, we find the charge-density-wave correlations to be a much more sensitive thermometer, useful for optimizing cooling into superfluid phases in future experiments.

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Debayan Mitra, Peter T. Brown, Elmer Guardado-Sanchez, Stanimir S. Kondov, Trithep Devakul, David A. Huse, Peter Schauss, Waseem S. Bakr. 2017-05-04. Quantum gas microscopy of an attractive Fermi-Hubbard system. https://doi.org/10.1038/nphys4297

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