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arXiv · 2312.01545

Diverse Entanglement Mechanisms in Multimode Nonlinear Continuous Variables

Da Zhang·David Barral·Yanpeng Zhang·Kamel Bencheikh
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Abstract

Non-Gaussian entangled states play a crucial role in harnessing quantum advantage in continuous-variable quantum information. However, how to fully characterize N-partite (N > 3) non-Gaussian entanglement without quantum state tomography remains elusive, leading to a very limited understanding of the underlying entanglement mechanism. Here, we propose several necessary and sufficient conditions for the positive-partial-transposition separability of multimode nonlinear quantum states resulting from high-order Hamiltonians and successive beam splitting operations. When applied to the initial state, the beam-splitter operations induce the emergence of different types of entanglement mechanisms, including pairwise high-order entanglement, collective high-order entanglement and the crossover between the two. We show numerically that for the four-mode scenario, the threshold for the existence of entanglement for any bipartition does not exceed the entanglement of the original state at fixed high-order moments. These results provide a new perspective for understanding multipartite nonlinear entanglement and will promote their application in quantum information processing.

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Da Zhang, David Barral, Yanpeng Zhang, Kamel Bencheikh. 2023-12-04. Diverse Entanglement Mechanisms in Multimode Nonlinear Continuous Variables. https://arxiv.org/abs/2312.01545

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