Synthetic gauge field and pseudospin-orbit interaction in a stacked two-dimensional ring-network lattice

Area of Science:

• Photonics
• Condensed Matter Physics
• Quantum Simulation

Background:

• Two-dimensional ring-network models simulate light propagation.
• These models can exhibit topological phases like Floquet-Weyl and Floquet-topological-insulator phases.
• Synthetic gauge fields and pseudospin-orbit interactions are key parameters.

Purpose of the Study:

• To study the effects of synthetic gauge fields and pseudospin-orbit interactions.
• To investigate the preservation of topological phases in a bosonic lattice model.
• To characterize the resulting band structures and topological invariants.

Main Methods:

• Utilized a stacked two-dimensional ring-network model for bosonic light propagation.
• Implemented synthetic gauge fields to create a Hofstadter-butterfly spectrum.
• Introduced pseudospin-orbit interaction as a mixing term between ring modes.
• Characterized topological gaps using winding numbers of S-matrices and Chern numbers.

Main Results:

• The synthetic magnetic field generates a 3D Hofstadter-butterfly spectrum.
• Pseudospin-orbit interaction destroys Floquet-topological-insulator phases.
• Floquet-Weyl phases with multiple Weyl points can be maintained by breaking space-inversion symmetry.
• Nonreciprocity is required for implementing both synthetic gauge fields and pseudospin-orbit interactions.

Conclusions:

• Synthetic gauge fields and pseudospin-orbit interactions significantly alter topological phases in photonic lattices.
• The Floquet-Weyl phase is robust to pseudospin-orbit interaction under broken space-inversion symmetry.
• This research provides insights into engineering topological phenomena in photonic systems.