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Autores principales: Kuang, Zeyu, Diekmann, Oliver, Fischer, Lorenz, Rotter, Stefan, Gonzalez-Ballestero, Carlos
Formato: Preprint
Publicado: 2025
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Acceso en línea:https://arxiv.org/abs/2512.20212
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author Kuang, Zeyu
Diekmann, Oliver
Fischer, Lorenz
Rotter, Stefan
Gonzalez-Ballestero, Carlos
author_facet Kuang, Zeyu
Diekmann, Oliver
Fischer, Lorenz
Rotter, Stefan
Gonzalez-Ballestero, Carlos
contents High-fidelity state transfer is fundamentally limited by time-reversal symmetry: one qubit emits a photon with a certain temporal pulse shape, whereas a second qubit requires the time-reversed pulse shape to efficiently absorb this photon. This limit is often overcome by introducing active elements. Here, we propose an alternative solution: by tailoring the dispersion relation of a waveguide, the photon pulse emitted by one qubit is passively reshaped into its time-reversed counterpart, thus enabling perfect absorption. We analytically derive the optimal dispersion relations in the limit of small and large qubit-qubit separations, and numerically extend our results to arbitrary separations via multiparameter optimization. We further propose a spatially inhomogeneous waveguide that renders the state transfer robust to variations in qubit separations. In all cases, we obtain near-unity transfer fidelity (>= 98%). Our dispersion-engineered waveguide provides a compact and passive route toward on-chip quantum networks, highlighting engineered dispersion as a powerful resource in waveguide quantum electrodynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2512_20212
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Perfect quantum state transfer in a dispersion-engineered waveguide
Kuang, Zeyu
Diekmann, Oliver
Fischer, Lorenz
Rotter, Stefan
Gonzalez-Ballestero, Carlos
Quantum Physics
Optics
High-fidelity state transfer is fundamentally limited by time-reversal symmetry: one qubit emits a photon with a certain temporal pulse shape, whereas a second qubit requires the time-reversed pulse shape to efficiently absorb this photon. This limit is often overcome by introducing active elements. Here, we propose an alternative solution: by tailoring the dispersion relation of a waveguide, the photon pulse emitted by one qubit is passively reshaped into its time-reversed counterpart, thus enabling perfect absorption. We analytically derive the optimal dispersion relations in the limit of small and large qubit-qubit separations, and numerically extend our results to arbitrary separations via multiparameter optimization. We further propose a spatially inhomogeneous waveguide that renders the state transfer robust to variations in qubit separations. In all cases, we obtain near-unity transfer fidelity (>= 98%). Our dispersion-engineered waveguide provides a compact and passive route toward on-chip quantum networks, highlighting engineered dispersion as a powerful resource in waveguide quantum electrodynamics.
title Perfect quantum state transfer in a dispersion-engineered waveguide
topic Quantum Physics
Optics
url https://arxiv.org/abs/2512.20212