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arXiv · 2511.20255

Escaping AB caging via Floquet engineering: photo-induced long-range interference in an all-band-flat model

Aamna Ahmed·Mónica Benito·Beatriz Pérez-González
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Abstract

Flat-band lattices hosting compact localized states are highly sensitive to external modulation, and the tailored design of a perturbation to imprint specific features becomes relevant. Here we show that periodic driving in the high-frequency regime transforms the all-flat-band diamond chain into one featuring two tunable quasi-flat bands and a residual flat band pinned at $E=0$. The interplay between lattice geometry and the symmetries of the driven system gives rise to drive-induced tunneling processes that redefine the interference conditions and open a controllable route to escaping Aharonov-Bohm caging. Under driving, the diamond chain effectively acquires the geometry of a dimerized lattice, exhibiting charge oscillations between opposite boundaries. This feature can be exploited to generate two-particle entanglement that is directly accessible experimentally. The resulting drive-engineered quasi-flat bands thus provide a versatile platform for manipulating quantum correlations, revealing a direct link between spectral fine structure and dynamical entanglement.

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Aamna Ahmed, Mónica Benito, Beatriz Pérez-González. 2025-11-25. Escaping AB caging via Floquet engineering: photo-induced long-range interference in an all-band-flat model. https://arxiv.org/abs/2511.20255

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