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

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.

arXiv comment7 pages, 4 figures, 1 table, supplemental material (6 pages, 1 figure)

References in corpus (44)

• Topological Insulators
• Topological insulators and superconductors
• Fault-tolerant quantum computation by anyons
• $Z_2$ Topological Order and the Quantum Spin Hall Effect
• Topological Insulators in Three Dimensions
• Topological Insulators with Inversion Symmetry
• Classification of topological quantum matter with symmetries
• Topological invariants of time-reversal-invariant band structures
• Topological insulators and superconductors: ten-fold way and dimensional hierarchy
• Artificial gauge potentials for neutral atoms
• Quantized Electric Multipole Insulators
• Periodic table for topological insulators and superconductors
• Higher-Order Topological Insulators
• Electric Multipole Moments, Topological Multipole Moment Pumping, and Chiral Hinge States in Crystalline Insulators
• $(d-2)$-dimensional edge states of rotation symmetry protected topological states
• Topolectrical circuit realization of topological corner modes
• Reflection symmetric second-order topological insulators and superconductors
• Observation of a phononic quadrupole topological insulator
• Three dimensional topological invariants for time reversal invariant Hamiltonians and the three dimensional quantum spin Hall effect
• Acoustic higher-order topological insulator on a Kagome lattice
• Higher-Order Topology in Bismuth
• Quantization of fractional corner charge in $C_n$-symmetric higher-order topological crystalline insulators
• The space group classification of topological band insulators
• Pyrochlore Photons: The U(1) Spin Liquid in a S=1/2 Three-Dimensional Frustrated Magnet
• The Hubbard Model
• The Flux-Phase of the Half-Filled Band
• Short-ranged RVB physics, quantum dimer models and Ising gauge theories
• Electric Field-Tuned Topological Phase Transition in Ultra-Thin Na3Bi - Towards a Topological Transistor
• Topological multicritical point in the Toric Code and 3D gauge Higgs Models
• Ground-State Phase Diagram of Quantum Heisenberg Antiferromagnets on the Anisotropic Dimerized Square Lattice
• Theta-terms in nonlinear sigma-models
• Fractional corner charges in spin-orbit coupled crystals
• Charged fermions coupled to ${\mathbb{Z}}_2$ gauge fields: Superfluidity, confinement and emergent Dirac fermions
• Orthogonal Metals: The simplest non-Fermi liquids
• Confinement transition of ${\mathbb{Z}}_2$ gauge theories coupled to massless fermions: emergent QCD${}_3$ and $SO(5)$ symmetry
• Z_2-slave-spin theory for strongly correlated fermions
• A simple fermionic model of deconfined phases and phase transitions
• Simple ${\mathbb{Z}}_2$ lattice gauge theories at finite fermion density
• Quantum phase transitions in Dirac fermion systems
• Quantum phases of two-dimensional ${\mathbb{Z}}_2$ gauge theory coupled to single-component fermion matter
• Ferromagnetically coupled dimers on the distorted Shastry-Sutherland lattice: Application to (CuCl)LaNb2O7
• Soluble limit and criticality of fermions in Z2 gauge theories
• Competing orders in the Dirac-like electronic structure and the non-linear sigma model with the topological terms
• Fermionic Superfluid from a Bilayer Band Insulator in an Optical Lattice

Cited by in corpus (1)

• Critical States of Fermions with ${\mathbb{Z}}_2$ Flux Disorder