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arXiv · 2609.22815

Asymmetric Two-Way Gaussian Quantum Steering in Coupled Lossy Waveguides

Hafsa Zia·Haleema Sadia Qureshi·Shakir Ullah·Mohamed Amazioug·Fazal Ghafoor
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Abstract

Quantum steering is an important type of quantum correlation with potential applications in one-sided device-independent (1SDI) quantum information protocols. In this contribution, we explore the time-dependent dynamics of Gaussian quantum steering in coupled lossy optical waveguides using the covariance matrix formalism. Optical dissipation is explicitly incorporated to account for realistic propagation losses in coupled waveguides. We systematically investigate the influence of the optical loss rate, purity, nonclassicality, and squeezing of the input Gaussian states on the generation and evolution of steering. The results demonstrate that increasing nonclassicality and squeezing enhances Gaussian steering, while optical loss and reduced purity progressively suppress it. However, a considerable amount of steering can persist over finite propagation intervals in the presence of optical loss. We further examine that steering is symmetric for input states with identical nonclassicality, while unequal nonclassicalities lead to directional steering asymmetry, offering a way to control the steering direction through input-state engineering. These results demonstrate that coupled optical waveguides can support controllable Gaussian quantum steering under practical loss conditions and offer a promising integrated-photonic platform for asymmetric quantum-information protocols, including 1SDI quantum key distribution (QKD) and quantum communication.

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Hafsa Zia, Haleema Sadia Qureshi, Shakir Ullah, Mohamed Amazioug, Fazal Ghafoor. 2026-09-19. Asymmetric Two-Way Gaussian Quantum Steering in Coupled Lossy Waveguides. https://arxiv.org/abs/2609.22815

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