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We consider the problem of determining whether genuine multipartite entanglement was produced in an experiment, without relying on a characterization of the systems observed or of the measurements performed. We present an n-partite…

Quantum Physics · Physics 2011-09-06 Jean-Daniel Bancal , Nicolas Gisin , Yeong-Cherng Liang , Stefano Pironio

This paper is concerned with all tests for continuous-variable entanglement that arise from linear combinations of second moments or variances of canonical coordinates, as they are commonly used in experiments to detect entanglement. All…

Quantum Physics · Physics 2009-11-11 P. Hyllus , J. Eisert

Detecting entanglement in many-body quantum systems is crucial but challenging, typically requiring multiple measurements. Here, we establish the class of states where measuring connected correlations in just $\textit{one}$ basis is…

Quantum Physics · Physics 2024-04-05 Roopayan Ghosh , Sougato Bose

The efficient witnessing and certification of entanglement is necessitated by its ubiquitous use in various aspects of quantum technologies. In the case of continuous-variable bipartite systems, the Shchukin--Vogel hierarchy gives necessary…

Quantum Physics · Physics 2025-09-09 Elena Callus , Martin Gärttner , Tobias Haas

The future of quantum communication relies on quantum networks composed by observers sharing multipartite quantum states. The certification of multipartite entanglement will be crucial to the usefulness of these networks. In many real…

Quantum Physics · Physics 2016-02-16 D. Cavalcanti , P. Skrzypczyk , G. H. Aguilar , R. V. Nery , P. H. Souto Ribeiro , S. P. Walborn

Entanglement between remote quantum mechanical systems enables a range of quantum information tasks in communication, computation and distributed sensing. Large numbers of entangled subsystems also require experimentally accessible and…

Quantum Physics · Physics 2026-03-23 Kai Ryen Bush , Kjetil Børkje

We study the genuine multipartite entanglement of arbitrary $n$-partite quantum states by representing the density matrices in terms of the generalized Pauli operators. We introduce a general framework for detecting genuine multipartite…

Quantum Physics · Physics 2023-08-08 Yu Lu , Shao-Ming Fei

Detecting and quantifying quantum entanglement of a given unknown state poses problems that are fundamentally important for quantum information processing. Surprisingly, no direct (i.e., without quantum tomography) universal experimental…

Quantum Physics · Physics 2015-04-13 Karol Bartkiewicz , Paweł Horodecki , Karel Lemr , Adam Miranowicz , Karol Życzkowski

The entanglement content of high-dimensional random pure states is almost maximal, nevertheless, we show that, due to the complexity of such states, the detection of their entanglement using witness operators is rather difficult. We discuss…

Quantum Physics · Physics 2007-10-24 Marko Znidaric , Tomaz Prosen , Giuliano Benenti , Giulio Casati

How can a multipartite single-photon path-entangled state be certified efficiently by means of local measurements? We address this question by constructing an entanglement witness based on local photon detections preceded by displacement…

We propose a hybrid approach to the experimental assessment of the genuine quantum features of a general system consisting of microscopic and macroscopic parts. We infer entanglement by combining dichotomic measurements on a bidimensional…

We provide a method for witnessing nonseparability of quantum processes on shared systems, which uses the channel-state duality. The method uses a maximally entangled state as a resource. We show that using the resource provides significant…

Quantum Physics · Physics 2021-05-19 Sohail , Ujjwal Sen

Bell diagonal states constitute a well-studied family of bipartite quantum states that arise naturally in various contexts in quantum information. In this paper we generalize the notion of Bell diagonal states to the case of unequal local…

Quantum Physics · Physics 2024-12-04 Johannes Moerland , Nikolai Wyderka , Hermann Kampermann , Dagmar Bruß

Loopholes present in an experimental set-up can significantly affect the reliability of entanglement detection. We discuss two methods for detection of entanglement: one is by using the positive partial transposition criterion after quantum…

Quantum Physics · Physics 2023-05-02 Paranjoy Chaki , Kornikar Sen , Ujjwal Sen

We present methods for detecting entanglement around symmetric Dicke states. In particular, we consider N-qubit symmetric Dicke states with N/2 excitations. In the first part of the paper we show that for large N these states have the…

Quantum Physics · Physics 2007-05-23 Geza Toth

Certifying entanglement for unknown quantum states experimentally is a fundamental problem in quantum computing and quantum physics. Because of being easy to implement, a most popular approach for this problem in modern quantum experiments…

Quantum Physics · Physics 2024-09-23 Ruiqi Zhang , Zhaohui Wei

We compute all third-order local invariants accessible via randomised measurements and employ them to derive separability criteria. The reconstruction of the invariants yields experimentally accessible entanglement criteria for multipartite…

Quantum Physics · Physics 2025-06-25 Giovanni Scala , Anindita Bera , Gniewomir Sarbicki

The experimental detection of multipartite entanglement usually requires a number of appropriately chosen local quantum measurements which are aligned with respect to a previously shared common reference frame. The latter, however, can be a…

Quantum Physics · Physics 2019-04-02 Andreas Ketterer , Nikolai Wyderka , Otfried Gühne

We introduce and study a class of entanglement criteria based on the idea of applying local contractions to an input multipartite state, and then computing the projective tensor norm of the output. More precisely, we apply to a mixed…

Quantum Physics · Physics 2020-10-14 Maria Anastasia Jivulescu , Cécilia Lancien , Ion Nechita

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