Experimental demonstration of non-bilocality with truly independent sources and strict locality constraints

Sun, Qi-Chao; Jiang, Yang-Fan; Bai, Bing; Zhang, Weijun; Li, Hao; Jiang, Xiao; Zhang, Jun; You, Lixing; Chen, Xianfeng; Wang, Zhen; Zhang, Qiang; Fan, Jingyun; Pan, Jian-Wei

doi:10.1038/s41566-019-0502-7

“…In the last 2 years, inequality (2) has been experimentally violated in a number of photonic setups 6,[33][34][35][36] . The first violation 33 exploited polarization-entangled photons and the measurements performed in the central node B relied on a complete Bell-state measurement.…”

Section: Resultsmentioning

confidence: 99%

Experimental violation of n-locality in a star quantum network[1]

Poderini

¹

,

Agresti

²

,

Marchese

³

et al. 2021

Conference on Lasers and Electro-Optics

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The launch of a satellite capable of distributing entanglement through long distances and the first loophole-free violation of Bell inequalities are milestones indicating a clear path for the establishment of quantum networks. However, nonlocality in networks with independent entanglement sources has only been experimentally verified in simple tripartite networks, via the violation of bilocality inequalities. Here, by using a scalable photonic platform, we implement star-shaped quantum networks consisting of up to five distant nodes and four independent entanglement sources. We exploit this platform to violate the chained n-locality inequality and thus witness, in a device-independent way, the emergence of nonlocal correlations among the nodes of the implemented networks. These results open new perspectives for quantum information processing applications in the relevant regime where the observed correlations are compatible with standard local hidden variable models but are nonclassical if the independence of the sources is taken into account.

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“…In the last 2 years, inequality (2) has been experimentally violated in a number of photonic setups 6,[33][34][35][36] . The first violation 33 exploited polarization-entangled photons and the measurements performed in the central node B relied on a complete Bell-state measurement.…”

Section: Resultsmentioning

confidence: 99%

“…For this reason, as already mentioned, we enforced the independence of the sources by adopting different laser devices, which, furthermore, were not relying on the same electric power source. Moreover, it requires the fair-sampling assumption, analogously to other most relevant experiments dealing with quantum networks 6,[33][34][35][36] . In the end, given that the measurements were not performed providing space-like separation, we are assuming the lack of uncontrolled communication channels among the measurements stages, located in the separated laboratories.…”

Section: Resultsmentioning

confidence: 99%

“…In spite of much recent theoretical advance, experimental implementations 6,[33][34][35] have been so far limited to the simplest possible quantum network, the bilocality model 21,22 . Such scenario is akin to the entanglement swapping experiment, involving two independent sources of entangled states, and only very recently was implemented while closing the locality and independence loopholes at the same time 36 .…”

mentioning

confidence: 99%

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Experimental violation of n-locality in a star quantum network

Poderini

¹

,

Agresti

²

,

Marchese

³

et al. 2020

View full text Add to dashboard Cite

The launch of a satellite capable of distributing entanglement through long distances and the first loophole-free violation of Bell inequalities are milestones indicating a clear path for the establishment of quantum networks. However, nonlocality in networks with independent entanglement sources has only been experimentally verified in simple tripartite networks, via the violation of bilocality inequalities. Here, by using a scalable photonic platform, we implement star-shaped quantum networks consisting of up to five distant nodes and four independent entanglement sources. We exploit this platform to violate the chained n-locality inequality and thus witness, in a device-independent way, the emergence of nonlocal correlations among the nodes of the implemented networks. These results open new perspectives for quantum information processing applications in the relevant regime where the observed correlations are compatible with standard local hidden variable models but are nonclassical if the independence of the sources is taken into account.

show abstract

“…In particular, the paradigmatic Bell-State Measurement (BSM), known from quantum teleportation 7 and entanglement-swapping 8 , is at the heart of many schemes for quantum correlations in networks (see e.g. [9][10][11][12] For the simplest network, quantum nonlocality has recently been experimentally demonstrated on optical platforms [13][14][15] .…”

Section: Introductionmentioning

confidence: 99%

Demonstrating the power of quantum computers, certification of highly entangled measurements and scalable quantum nonlocality

Bäumer

¹

,

Gisin

²

,

Tavakoli

³

2021

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Increasingly sophisticated quantum computers motivate the exploration of their abilities in certifying genuine quantum phenomena. Here, we demonstrate the power of state-of-the-art IBM quantum computers in correlation experiments inspired by quantum networks. Our experiments feature up to 12 qubits and require the implementation of paradigmatic Bell-State Measurements for scalable entanglement-swapping. First, we demonstrate quantum correlations that defy classical models in up to nine-qubit systems while only assuming that the quantum computer operates on qubits. Harvesting these quantum advantages, we are able to certify 82 basis elements as entangled in a 512-outcome measurement. Then, we relax the qubit assumption and consider quantum nonlocality in a scenario with multiple independent entangled states arranged in a star configuration. We report quantum violations of source-independent Bell inequalities for up to ten qubits. Our results demonstrate the ability of quantum computers to outperform classical limitations and certify scalable entangled measurements.

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Experimental demonstration of non-bilocality with truly independent sources and strict locality constraints

Cited by 64 publications

References 44 publications

Experimental violation of n-locality in a star quantum network[1]

Experimental violation of n-locality in a star quantum network[1]

Experimental violation of n-locality in a star quantum network

Demonstrating the power of quantum computers, certification of highly entangled measurements and scalable quantum nonlocality

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