Robust quantum valley Hall effect for vortices in an interacting bosonic quantum fluid

Area of Science:

• Topological physics
• Quantum optics
• Condensed matter physics

Background:

• Topologically protected transport is crucial for robust information transfer.
• Existing methods like the quantum spin Hall effect are not directly applicable to photons and bosons.
• Symmetry-protected pseudospins are lacking in these systems.

Purpose of the Study:

• To demonstrate a novel mechanism for topologically protected pseudospin transport in bosons.
• To utilize quantum vortices as a source of topological protection.
• To investigate valley pseudospin transport in a Bose-Einstein condensate system.

Main Methods:

• Utilizing a Bose-Einstein condensate in a quantum valley Hall system with staggered honeycomb lattices.
• Introducing a quantum vortex as a real-space topological excitation.
• Analyzing the coupling between vortex winding and bulk Bloch band valley.

Main Results:

• Demonstrated chiral vortex propagation along zigzag interfaces.
• Showcased topological protection via vortex winding, preventing pseudospin mixing.
• Achieved robust valley pseudospin transport without resonant backscattering.

Conclusions:

• Quantum vortices can provide the necessary topological protection for pseudospin transport in bosons.
• This work offers a new pathway for realizing robust quantum information transfer in photonic and bosonic systems.
• The findings open avenues for novel topological quantum devices.