Higher-Order Topological Peierls Insulator in a Two-Dimensional Atom-Cavity System

Area of Science:

• Quantum Simulation
• Condensed Matter Physics
• Atomic Physics

Background:

• The Su-Schrieffer-Heeger (SSH) model describes 1D bond dimerization driven by electron-phonon interactions.
• Topological phases of matter exhibit unique properties protected by topology.
• Higher-order topological phases host protected states at boundaries of lower dimensionality.

Purpose of the Study:

• Investigate novel topological phases in ultracold atomic systems.
• Explore photon-mediated interactions for emergent phenomena.
• Generalize 1D topological models to 2D using bosonic atoms.

Main Methods:

• Utilizing a 2D system of ultracold bosonic atoms in an optical cavity.
• Inducing photon-mediated interactions to drive atomic correlations.
• Characterizing the topological phase using many-body invariants and entanglement analysis.
• Employing adiabatic protocols for experimental preparation.

Main Results:

• Observed a plaquette-ordered bond pattern in the atomic ground state, analogous to a 2D Peierls transition.
• Demonstrated the emergence of a nontrivial topological gap in 2D.
• Identified a higher-order topological phase hosting corner states.
• Confirmed the crucial role of bosonic statistics in forming the plaquette structure.

Conclusions:

• Atomic quantum simulators can realize novel strongly correlated topological phenomena.
• Photon-mediated interactions offer a pathway to engineer complex topological phases.
• The discovered higher-order topological Peierls insulator provides a new platform for studying topological matter.