Experimental ladder proof of Hardy's nonlocality for high-dimensional quantum systems

Chen, Lixiang; Zhang, Wuhong; Wu, Ziwen; Wang, Jikang; Fickler, Robert; Karimi, Ebrahim

doi:10.1103/physreva.96.022115

Cited by 17 publications

(4 citation statements)

References 40 publications

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“…Boschi and co-workers developed the ladder version of Hardy's paradox for two spin-1/2 particles, significantly increasing the probability of the nonlocal events [7]. It was also theoretically proved by Rabelo [8] that there exists an analogue of Tsirelson's bound [9] for Hardy's test of nonlocality, irrespective of the dimension of the system, which was subsequently confirmed in experiment [10]. Recent progress was also made to generalize the Hardy's paradox into a most general framework of n-qubit system [11].…”

Section: Introductionmentioning

confidence: 98%

Orbital-angular-momentum-based experimental test of Hardy's paradox for multisetting and multidimensional systems

Zhang,

Qiu,

et al. 2020

Preprint

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Characterizing high-dimensional entangled states is of crucial importance in quantum information science and technology. Recent theoretical progress has been made to extend the Hardy's paradox into a general scenario with multisetting multidimensional systems, which can surpass the bound limited by the original version. Hitherto, no experimental verification has been conducted to verify such a Hardy's paradox, as most of previous experimental efforts were restricted to two-dimensional systems. Here, based on two-photon high-dimensional orbital angular momentum (OAM) entanglement, we report the first experiment to demonstrate the Hardy's paradox for multiple settings and multiple outcomes. We demonstrate the paradox for two-setting higher-dimensional OAM subspaces up to d = 7, which reveals that the nonlocal events increase with the dimension. Furthermore, we showcase the nonlocality with an experimentally recording probability of 36.77% for five-setting three-dimensional OAM subspace via entanglement concentration, and thus showing a sharper contradiction between quantum mechanics and classical theory.

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Section: Introductionmentioning

confidence: 98%

Orbital-angular-momentum-based experimental test of Hardy's paradox for multisetting and multidimensional systems

Zhang,

Qiu,

et al. 2020

Preprint

Self Cite

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“…Hardy's test has been realized experimentally using two spin-half particles 29 , or photon pairs entangled in different degrees of freedom such as polarization 30 , energy-time 31,32 , and orbital angular momentum (OAM) 33,34 . Recently, the Hardy's theory was also extended to n-particle or two-particle system even with a high dimensionality [35][36][37][38] . Therefore, it has been routinely considered as a fundamental quantum effect to showcase the existence of quantum nonlocality.…”

Section: Introductionmentioning

confidence: 99%

Imaging hyper-entanglement based on the Hardy-type nonlocality paradox

Zhang¹,

Qiu²,

Zhang³

et al. 2021

Preprint

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The concept of quantum entanglement and hyper-entanglement, lying at the heart of quantum information science and technologies, is physically counter-intuitive and mathematically elusive. We design a polarization-encoded ghost imaging system based on the frame of Hardy nonlocality paradox to visualize the evidence of quantum hyper-entanglement by capturing purely nonlocal photonic events. In two-photon polarization-spatial-mode hyper-entangled state, spatial entanglement conveys the ghost images while polarization entanglement encodes the imaging channels. Then whether imaging the single ghost image of a skull-shape object or not can be a direct yet intuitive signature to support or defy quantum mechanics. We use the contrast-to-noise ratio of ghost images to macroscopically characterize the degree of the violation of locality. We also showcase the nonlocal behavior of violating the locality with a reasonable confidence level of 75%, microscopically at the single-pixel level. Our strategy not only sheds new light on the fundamental issue of quantum mechanics, but also holds promise for developing hyper-entanglement-based quantum imaging technology.

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“…Despite great efforts have been made by experimentalists [43][44][45][46][47][48][49][50], loophole-free Hardy's paradox test is still missing, which limits significantly its related quantum information applications. In this letter, we challenge the local realism with Hardy's violation by utilizing polarization-entangled photon pairs with a high-fidelity of up to 99.10%, fast random basis choices, and high detection efficiency of around 82.2% to obtain the joint probabilities of Alice and Bob.…”

mentioning

confidence: 99%

Infectious Hospital Area, the First Affiliated Hospital of University of Science and Technology of China, Hefei, China

Zhao¹,

Hu²,

Xue³

et al. 2021

BEBM

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With advances in deep learning, neural network based speech enhancement (SE) has developed rapidly in the last decade. Meanwhile, the self-supervised pre-trained model and vector quantization (VQ) have achieved excellent performance on many speech-related tasks, while they are less explored on SE. As it was shown in our previous work that utilizing a VQ module to discretize noisy speech representations is beneficial for speech denoising, in this work we therefore study the impact of using VQ at different layers with different number of codebooks. Different VQ modules indeed enable to extract multiplegranularity speech features. Following an attention mechanism, the contextual features extracted by a pre-trained model are fused with the local features extracted by the encoder, such that both global and local information are preserved to reconstruct the enhanced speech. Experimental results on the Valentini dataset show that the proposed model can improve the SE performance, where the impact of choosing pre-trained models is also revealed.

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Experimental ladder proof of Hardy's nonlocality for high-dimensional quantum systems

Cited by 17 publications

References 40 publications

Orbital-angular-momentum-based experimental test of Hardy's paradox for multisetting and multidimensional systems

Orbital-angular-momentum-based experimental test of Hardy's paradox for multisetting and multidimensional systems

Imaging hyper-entanglement based on the Hardy-type nonlocality paradox

Infectious Hospital Area, the First Affiliated Hospital of University of Science and Technology of China, Hefei, China

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