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The Bell state measurement (BSM) is the projection of two qubits onto four orthogonal maximally entangled states. Here, we first propose how to appropriately define more general BSMs, that have more than four possible outcomes, and then…

Quantum Physics · Physics 2024-10-08 Amanda Wei , Gabriele Cobucci , Armin Tavakoli

Previous theoretical works showed that all pure two-qubit entangled states can generate one bit of local randomness and can be self-tested through the violation of proper Bell inequalities. We report an experiment in which nearly pure…

Quantum Physics · Physics 2019-03-14 S. Gómez , A. Mattar , I. Machuca , E. S. Gómez , D. Cavalcanti , O. Jiménez Farías , A. Acín , G. Lima

Many-body quantum systems can be characterised using the notions of \emph{k}-separability and entanglement depth. A quantum state is \emph{k}-separable if it can be expressed as a mixture of \emph{k} entangled subsystems, and its…

Quantum entanglement is essential to the development of quantum computation, communications, and technology. The controlled SWAP test, widely used for state comparison, can be adapted to an efficient and useful test for entanglement of a…

Quantum Physics · Physics 2022-01-12 Steph Foulds , Viv Kendon , Tim Spiller

Entanglement is a key property in the development of quantum technologies and in the study of quantum many-body simulations. However, entanglement measurement typically requires quantum full-state tomography (FST). Here we present a neural…

Quantum Physics · Physics 2022-09-20 Yulei Huang , Liangyu Che , Chao Wei , Feng Xu , Xinfang Nie , Jun Li , Dawei Lu , Tao Xin

Certifying maximal quantum randomness without assumptions about system dimension remains a pivotal challenge for secure communication and foundational studies. Here, we introduce a generalized framework to directly certify maximal…

Quantum Physics · Physics 2025-07-15 Tianqi Zheng , Yi Li , Yu Xiang , Qiongyi He

We put forward a general classification for a structural description of the entanglement present in compound entities experimentally violating Bell's inequalities, making use of a new entanglement scheme that we developed recently. Our…

Artificial Intelligence · Computer Science 2015-12-31 Diederik Aerts , Sandro Sozzo

Bell inequalities constitute a key tool in quantum information theory: they not only allow one to reveal nonlocality in composite quantum systems, but, more importantly, they can be used to certify relevant properties thereof. We provide a…

Quantum Physics · Physics 2020-01-22 F. Baccari , R. Augusiak , I. Šupić , J. Tura , A. Acín

In single-particle entanglement (SPE) two degrees of freedom of a single particle are entangled. SPE is a resource that can be exploited both in quantum communication protocols and in experimental tests of noncontextuality based on the…

Quantum Physics · Physics 2021-08-18 Sonia Mazzucchi , Nicolò Leone , Stefano Azzini , Lorenzo Pavesi , Valter Moretti

By performing local projective measurements on a two-qubit entangled state one can certify in a device-independent way up to one bit of randomness. We show here that general measurements, defined by positive-operator-valued measures, can…

Quantum Physics · Physics 2016-04-20 Antonio Acín , Stefano Pironio , Tamás Vértesi , Peter Wittek

Contextuality is a foundational phenomenon underlying key differences between quantum theory and classical realistic descriptions of the world. Here we propose an experimental test which is capable of revealing contextuality in all qutrit…

Quantum Physics · Physics 2013-09-23 Jayne Thompson , Robert Pisarczyk , Pawel Kurzynski , Dagomir Kaszlikowski

Bounds analogous to entropic uncertainty relations allow one to design practical tests to detect quantum entanglement by a collective measurement performed on several copies of the state analyzed. This approach, initially worked out for…

Quantum Physics · Physics 2013-01-04 Łukasz Rudnicki , Zbigniew Puchała , Paweł Horodecki , Karol Życzkowski

Quantum entanglement swapping is one of the most promising ways to realize the quantum connection among local quantum nodes. In this Letter, we present an experimental demonstration of the entanglement swapping between two independent…

Quantum Physics · Physics 2016-12-21 Xiaolong Su , Caixing Tian , Xiaowei Deng , Qiang Li , Changde Xie , Kunchi Peng

Mutually unbiased bases (MUBs) provide a standard tool in the verification of quantum states, especially when harnessing a complete set for optimal quantum state tomography. In this work, we investigate the detection of entanglement via…

Quantum Physics · Physics 2021-09-14 B. C. Hiesmayr , D. McNulty , S. Baek , S. Singha Roy , J. Bae , D. Chruściński

Cluster states serve as the central physical resource for the measurement-based quantum computation. We here present a simple experimental demonstration of the scalable cluster-state-construction scheme proposed by Browne and Rudolph. In…

Quantum Physics · Physics 2015-06-26 An-Ning Zhang , Chao-Yang Lu , Xiao-Qi Zhou , Yu-Ao Chen , Zhi Zhao , Tao Yang , Jian-Wei Pan

High-dimensional quantum systems offer a number of advantages in larger information capacity, stronger noise resiliency, higher improved efficiency and accuracy over the qubit systems. In quantum communication the maximally entangled states…

Quantum Physics · Physics 2026-04-15 Si-Qi Du , Guo-Zhu Song , Hai-Rui Wei

The network structure offers in principle the possibility for novel forms of quantum nonlocal correlations, that are proper to networks and cannot be traced back to standard quantum Bell nonlocality. Here we define a notion of genuine…

Quantum Physics · Physics 2022-08-24 Ivan Šupić , Jean-Daniel Bancal , Yu Cai , Nicolas Brunner

Experimental detection of entanglement of an arbitrary state of a given bipartite system is crucial for exploring many areas of quantum information. But such a detection should be made in a device independent way if the preparation process…

Quantum Physics · Physics 2017-11-22 Arindam Mallick , Sibasish Ghosh

Certifying entanglement is an important step in the development of many quantum technologies, especially for higher-dimensional systems, where entanglement promises increased capabilities for quantum communication and computation. A key…

Quantum Physics · Physics 2025-03-21 Nicky Kai Hong Li , Marcus Huber , Nicolai Friis

We search a simplest and minimal way to determine whether a given quantum system is entangled or separable. For this end, we propose binary correlation measurements in which restricted knowledge of only zero or non-zero correlations is…

Quantum Physics · Physics 2021-06-29 Toru Ohira