Quantum 2025 – scientific programme
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MON: Monday Contributed Sessions
MON 23: Poster Session: Fundamental Aspects and Model Systems
MON 23.66: Poster
Monday, September 8, 2025, 18:30–20:30, ZHG Foyer 1. OG
Aharonov-Bohm caging in classical photonic simulators through Floquet engineering — •Shamarita Deb1, Julian Schulz2, Georg von Freymann2, and Christina Jörg2 — 1Max planck Institute for Chemical physics of solids ( CPfS), Nöthnitzer Straße 40, 01187 Dresden — 2RPTU - Rheinland Pfälzische Technische Universität, Erwin Schrödinger Straße 56, 67663 Kaiserslautern
The Aharonov-Bohm (AB) effect is a striking quantum phenomenon, demonstrating that even in regions without magnetic field, a vector potential can induce a measurable phase shift in an electron's wavefunction. In a lattice system, this principle gives rise to Aharonov-Bohm caging, where electrons become caged or spatially localized within a specific region in the structure due to destructive interference, leading to a complete suppression of their transport. We realize this phenomenon in a classical photonic simulator: a closed array of six waveguides fabricated by femtosecond direct laser writing. This analogy becomes possible because the paraxial Helmholtz equation governing light propagation maps directly onto the Schrödinger equation, allowing waveguide arrays to emulate tight-binding electronic systems. We implement a two-frequency Floquet modulation along the propagation direction analogous to the vector potential which modifies the effective coupling between sites. The resulting complex coupling acquires a phase factor whose accumulated sum around the closed chain defines an artificial effective flux that governs the interference. Using tight-binding model and beam-propagation simulations, we designed and fabricated nine structures with different coupling phases to observe the interference effect. Experiments at the optimized parameters reveal bounded oscillations and localization at the predicted caging phase condition. A special case of this Floquet modulation is the single frequency limit, which results in dynamic localization highlighting the versatility of Floquet-engineered photonic lattices to mimic and explore physics of solid state systems.