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arXiv · 2212.14625

Obstructed Atomic Insulators and Superfluids of Fermions Coupled to $\mathbb{Z}_2$ Gauge Fields

Bhandaru Phani Parasar·Vijay B. Shenoy
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Abstract

We study spin-$\frac{1}{2}$ fermions coupled to $\mathbb{Z}_2$ gauge fields on a lattice. We show how a spatial modulation of the fermion hopping allows for the realization of various obstructed atomic insulators that host higher-order band topology. Studying the effect of quantum dynamics of the gauge fields within a simplified model, we find a rich phase diagram of this system with a number of superfluid phases arising from the attractive interactions meditated by the gauge fields. A key finding of this work is that the evolution from the Bardeen-Cooper-Schrieffer (BCS) superfluid state to a Bose-Einstein condensate (BEC) of tightly bound pairs occurs via the realization of these different superfluid phases separated by first-order transitions.

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Bhandaru Phani Parasar, Vijay B. Shenoy. 2022-12-30. Obstructed Atomic Insulators and Superfluids of Fermions Coupled to $\mathbb{Z}_2$ Gauge Fields. https://doi.org/10.1103/physrevb.107.245142

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