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Related papers: Annihilating and creating nonlocality without enta…

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As a striking manifestation of quantum entanglement, nonlocality has long played a pivotal role in shaping our understanding of the quantum world. When considering a Bell test involving three parties, we may even find a remarkable situation…

Quantum Physics · Physics 2026-04-10 Kai-Siang Chen , Gelo Noel M. Tabia , Chung-Yun Hsieh , Yu-Chun Yin , Yeong-Cherng Liang

The outcomes of local measurements made on entangled systems can be certified to be random provided that the generated statistics violate a Bell inequality. This way of producing randomness relies only on a minimal set of assumptions…

Two pure orthogonal quantum states can be perfectly distinguished by sequential local action of multiple pairs of parties. However, this process typically leads to the complete dissolution of entanglement in the states being discriminated.…

Quantum Physics · Physics 2025-06-10 Debarupa Saha , Priya Ghosh , Kornikar Sen , Chirag Srivastava , Ujjwal Sen

An alternative proof for existence of ``quantum nonlocality without entanglement'', i.e. existence of variables with product-state eigenstates which cannot be measured locally, is presented. A simple``nonlocal'' variable for the case of…

Quantum Physics · Physics 2009-11-07 Berry Groisman , Lev Vaidman

Entanglement, the essential resource in quantum information processing, should be witnessed in many tasks such as quantum computing and quantum communication. The conventional entanglement witness method, relying on an idealized…

Quantum Physics · Physics 2014-04-17 Ping Xu , Xiao Yuan , Luo-Kan Chen , He Lu , Xing-Can Yao , Xiongfeng Ma , Yu-Ao Chen , Jian-Wei Pan

While all bipartite pure entangled states are known to generate correlations violating a Bell inequality, and are therefore nonlocal, the quantitative relation between pure-state entanglement and nonlocality is poorly understood. In fact,…

Quantum Physics · Physics 2018-08-14 Victoria Lipinska , Florian Curchod , Alejandro Máttar , Antonio Acín

We investigate the quantum nonlocality via the discrimination on two, three and four-qubit orthogonal product bases (OPBs). We show that every two-qubit, and some three and four-qubit OPBs can be locally distinguished. It turns out that the…

Quantum Physics · Physics 2023-10-02 Lin Chen , Yutong Jiang

Complex numbers are central to the formulation of quantum mechanics, yet their role as a genuine resource is only beginning to be understood. In this work, we demonstrate that quantum states with intrinsically complex amplitudes provide a…

Quantum Physics · Physics 2026-04-09 Subrata Bera , Indranil Biswas , Atanu Bhunia , Indrani Chattopadhyay , Debasis Sarkar

We consider unambiguous discrimination of two separable bipartite states, one being pure and the other being a rank-2 mixed state. There is a gap between the optimal success probability under global measurements and the one achieved by…

Quantum Physics · Physics 2007-09-21 Masato Koashi , Fumitaka Takenaga , Takashi Yamamoto , Nobuyuki Imoto

A set of orthogonal product states of a composite Hilbert space is genuinely nonlocal if the states are locally indistinguishable across any bipartition. In this work, we construct a minimal set of party asymmetry genuine nonlocal set in…

Quantum Physics · Physics 2025-08-21 Atanu Bhunia , Indrani Chattopadhyay , Debasis Sarkar

Quantum theory features several phenomena which can be considered as resources for information processing tasks. Some of these effects, such as entanglement, arise in a nonlocal scenario, where a quantum state is distributed between…

Quantum Physics · Physics 2024-07-22 Martin Plávala , Otfried Gühne

Entanglement and Bell nonlocality are known to be inequivalent: there exist entangled states that admit a local hidden-variable model for all local measurements. Here we show that this gap disappears in a minimal broadcast extension of the…

Quantum Physics · Physics 2025-12-18 Pavel Sekatski , Jef Pauwels

The multipartite correlations derived from local measurements on some composite quantum systems are inconsistent with those reproduced classically. This inconsistency is known as quantum nonlocality and shows a milestone in the foundations…

Quantum Physics · Physics 2018-10-17 Ming-Xing Luo

The uncertainty principle may be considered as giving rise to the notion of incompatibility of observables. A pack of quantum measurements that cannot be measured simultaneously is said to form a set of incompatible measurements. Every set…

Quantum Physics · Physics 2024-01-19 Kornikar Sen , Saronath Halder , Ujjwal Sen

Based on a recently proposed model of physical reality and an underlying criterion of nonlocality for contexts [A. L. O. Bilobran and R. M. Angelo, Europhys. Lett. {\bf 112}, 40005 (2015)], we introduce a quantifier of realism-based…

Quantum Physics · Physics 2018-02-06 V. S. Gomes , R. M. Angelo

Nonlocality without entanglement is an interesting field. A manifestation of quantum nonlocality without entanglement is the local indistinguishability of a set of orthogonal product states. In this paper we analyze the character of…

Quantum Physics · Physics 2009-11-10 Ping Xing Chen , Cheng Zu Li

Entanglement and nonlocality are both fundamental aspects of quantum theory, and play a prominent role in quantum information science. The exact relation between entanglement and nonlocality is however still poorly understood. Here we make…

Quantum Physics · Physics 2012-01-24 Tamas Vertesi , Nicolas Brunner

In spite of many results in quantum information theory, the complex nature of compound systems is far from being clear. In general the information is a mixture of local, and non-local ("quantum") information. To make this point more clear,…

Choosing four entangled stets to form an orthogonal and complete basis for a two-particle system, we argue that a local hidden variable model should give the probability of each entangled state if the two-particle system is described by a…

Quantum Physics · Physics 2009-11-07 Xiao-Hua Wu , HongShi Zong , Hou-Rong Pang , Fan Wang

We propose an innovative method to enhance the detection and protection of quantum entanglement, a cornerstone of quantum mechanics with applications in computing, communication, and beyond. While entanglement can be represented through…

Quantum Physics · Physics 2024-12-17 Haruki Matsunaga , Le Bin Ho