Topological spin texture of chiral edge states in photonic two-dimensional quantum walks

Abstract

Topological insulators host topology-linked boundary states, whose spin and charge degrees of freedom could be exploited to design topological devices with enhanced functionality. We experimentally observe that dissipationless chiral edge states in a spin-orbit coupled anomalous Floquet topological phase exhibit topological spin texture on boundaries, realized via a two-dimensional quantum walk. Our experiment shows that, for a walker traveling around a closed loop along the boundary in real space, its spin evolves and winds through a great circle on the Bloch sphere, which implies that edge-spin texture has nontrivial winding. This winding is linked to the bulk Dirac Hamiltonian around the energy-gap opening point. Our experiment confirms that two-dimensional anomalous Floquet topological systems exhibit topological spin texture on the boundary, which could inspire novel topology-based spintronic phenomena and devices.

6 pages, 4 figures

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Cited by in corpus (4)

• Self acceleration from spectral geometry in dissipative quantum-walk dynamics
• Floquet band engineering with Bloch oscillations
• Quantum walks on random lattices: Diffusion, localization and the absence of parametric quantum speed-up
• Berry Curvature and Bulk-Boundary Correspondence from Transport Measurement for Photonic Chern Bands