Genuine Multipartite Nonlocality Is Intrinsic to Quantum Networks

Contreras-Tejada, Patricia; Palazuelos, Carlos; Vicente, Julio I. de

doi:10.1103/physrevlett.126.040501

“…Concerning quantum correlations, several initial works appeared in the last year, suggesting slightly different definitions of network entanglement 25 – 28 . These have been further investigated 29 – 31 and methods from the classical realm have been extended to the quantum scenario 32 . Still, the present results are limited to simple networks like the triangle network, noise-free networks or networks build from specific quantum states, or bounded to small dimensions due to numerical limitations.…”

Section: Introductionmentioning

confidence: 99%

Symmetries in quantum networks lead to no-go theorems for entanglement distribution and to verification techniques

Hansenne

¹

,

Xu

²

,

Kraft

³

et al. 2022

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Quantum networks are promising tools for the implementation of long-range quantum communication. The characterization of quantum correlations in networks and their usefulness for information processing is therefore central for the progress of the field, but so far only results for small basic network structures or pure quantum states are known. Here we show that symmetries provide a versatile tool for the analysis of correlations in quantum networks. We provide an analytical approach to characterize correlations in large network structures with arbitrary topologies. As examples, we show that entangled quantum states with a bosonic or fermionic symmetry can not be generated in networks; moreover, cluster and graph states are not accessible. Our methods can be used to design certification methods for the functionality of specific links in a network and have implications for the design of future network structures.

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“…For instance, certain biseparable states have been shown to lead to secure multipartite secret key exploiting their GME-activability [20]. As another example, all connected networks made out by sharing bipartite pure entangled states happen to be GME and genuine multipartite non-locality can be extracted out of them [21,22]. From a more fundamental point of view, although examples of activation and superactivation are not infrequent in quantum information theory (they appear e.g.…”

Section: Introductionmentioning

confidence: 99%

Genuine multipartite entanglement of quantum states in the multiple-copy scenario

Palazuelos,

de Vicente

2022

Preprint

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Genuine multipartite entanglement (GME) is considered a powerful form of entanglement since it corresponds to those states that are not biseparable, i.e. a mixture of partially separable states across different bipartitions of the parties. In this work we study this phenomenon in the multiple-copy regime, where many perfect copies of a given state can be produced and controlled. In this scenario the above definition leads to subtle intricacies as biseparable states can be GME-activatable, i.e. several copies of a biseparable state can display GME. We show that the set of GME-activatable states admits a simple characterization: a state is GME-activatable if and only if it is not partially separable across one bipartition of the parties. This leads to the second question of whether there is a general upper bound in the number of copies that needs to be considered in order to observe the activation of GME, which we answer in the negative. In particular, by providing an explicit construction, we prove that for any number of parties and any number k ∈ N there exist GMEactivatable multipartite states of fixed (i.e. independent of k) local dimensions such that k copies of them remain biseparable.

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“…Concerning quantum correlations, several initial works appeared in the last year, suggesting slightly different definitions of network entanglement [25][26][27][28]. These have been further investigated [29][30][31] and methods from the classical realm have been extended to the quantum scenario [32]. Still, the present results are limited to simple networks like the triangle network, noise-free networks or networks build from specific quantum states, or bounded to small dimensions due to numerical limitations.…”

Section: Introductionmentioning

confidence: 99%

Quantum Networks and Symmetries

Hansenne¹,

Xu

²

,

Kraft³

et al. 2021

Preprint

0

View full text Add to dashboard Cite

Quantum networks are promising tools for the implementation of long-range quantum communication. The characterization of quantum correlations in networks and their usefulness for information processing is therefore central for the progress of the field, but so far only results for small basic network structures or pure quantum states are known. Here we show that symmetries provide a versatile tool for the analysis of correlations in quantum networks. We provide an analytical approach to characterize correlations in large network structures with arbitrary topologies. As examples, we show that entangled quantum states with a bosonic or fermionic symmetry can not be generated in networks; moreover, cluster and graph states are not accessible. Our methods can be used to design certification methods for the functionality of specific links in a network and have implications for the design of future network structures.

show abstract

Genuine Multipartite Nonlocality Is Intrinsic to Quantum Networks

Cited by 58 publications

References 63 publications

Symmetries in quantum networks lead to no-go theorems for entanglement distribution and to verification techniques

Symmetries in quantum networks lead to no-go theorems for entanglement distribution and to verification techniques

Genuine multipartite entanglement of quantum states in the multiple-copy scenario

Quantum Networks and Symmetries

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