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arXiv · 2609.32125

Counterdiabatic quasi-Floquet control for the generation of entangled BICs using giant atoms

Alexis R. Legón·Pedro Orellana·Ariel Norambuena
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Abstract

Bound states in the continuum (BICs) provide a mechanism for preserving entanglement in waveguide quantum electrodynamics. Here, using quantum control techniques in a configuration of two braided giant atoms, we propose a robust approach to create high-fidelity entangled BICs. The protocol combines quasi-Floquet modulation of the effective atom--waveguide couplings with an independent phase-controlled atomic exchange, which provides restricted counterdiabatic assistance for preparing the complete dressed BIC. In the lossless effective model, we obtain a full-state BIC fidelity of $0.99992$ and an unconditional atomic Bell fidelity of $0.99588$ using a fast control protocol. Microscopic finite-mode simulations validate the central-sideband description during the passage, while static calibration-error scans quantify its control tolerances. A separate microscopic study with relaxation and dephasing, using experimentally motivated component scales, identifies a finite useful entanglement window and a benefit from shaping the coupling envelopes. These results support controlled preparation, retention, and retrieval of dressed entanglement within the stated control and noise assumptions.

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Alexis R. Legón, Pedro Orellana, Ariel Norambuena. 2026-09-26. Counterdiabatic quasi-Floquet control for the generation of entangled BICs using giant atoms. https://arxiv.org/abs/2609.32125

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