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The controlled generation of entangled states and their subsequent detection are integral aspects of quantum information science. In this work, we analyse the application of nonlinear witnesses to the verification of entanglement, and we…

Quantum Physics · Physics 2012-10-04 Megan Agnew , Jeff Z. Salvail , Jonathan Leach , Robert W. Boyd

In this work, new types of EWs are introduced. They are constructed by using real skew-symmetric operators defined on a single party subsystem of a bipartite dxd system and a maximal entangled state in that system. A canonical form for…

Quantum Physics · Physics 2015-05-19 M. A. Jafarizadeh , N. Behzadi

We show the properties and characterization of coherence witnesses. We show methods for constructing coherence witnesses for an arbitrary coherent state. We investigate the problem of finding common coherence witnesses for certain class of…

Quantum Physics · Physics 2021-09-09 Bang-Hai Wang , Zi-Heng Ding , Zhihao Ma , Shao-Ming Fei

Entanglement is solely a quantum property and it can be extremely helpful to test the physics beyond the Standard Model in tabletop experiments with the advent of future quantum technologies. In this work, we provide an entanglement-based…

Quantum Physics · Physics 2025-11-20 Pablo Guillermo Carmona Rufo , Ayush Kumar , Carlos Sabín , Anupam Mazumdar

We frame entanglement detection as a problem of random variable inference to introduce a quantitative method to measure and understand whether entanglement witnesses lead to an efficient procedure for that task. Hence we quantify how many…

Quantum Physics · Physics 2023-08-16 Paulo J. Cavalcanti , Giovanni Scala , Antonio Mandarino , Cosmo Lupo

We propose a set of linear quantum entanglement witnesses constituted by local quantum-mechanical observables with each two possible measurement outcomes. These witnesses detect all the entangled resources which give rise to a better…

Quantum Physics · Physics 2012-05-04 Ming-Jing Zhao , Shao-Ming Fei , Xianqing Li-Jost

We investigate how stabilizer theory can be used for constructing sufficient conditions for entanglement. First, we show how entanglement witnesses can be derived for a given state, provided some stabilizing operators of the state are…

Quantum Physics · Physics 2007-05-23 Geza Toth , Otfried Guehne

Entanglement witness is an effective method to detect entanglement in unknown states without doing full tomography. One of the most widespread schemes of witnessing entanglement is measuring its fidelity with respect to a pure entangled…

Quantum Physics · Physics 2021-03-19 Yongtao Zhan , Hoi-Kwong Lo

Suppose an experimentalist wishes to verify that his apparatus produces entangled quantum states. A finite amount of data cannot conclusively demonstrate entanglement, so drawing conclusions from real-world data requires statistical…

Quantum Physics · Physics 2010-10-22 Robin Blume-Kohout , Jun O. S. Yin , S. J. van Enk

In this paper, we present a characterization of optimal entanglement witnesses in terms of positive maps and then provide a general method of checking optimality of entanglement witnesses. Applying it, we obtain new indecomposable optimal…

Quantum Physics · Physics 2015-05-30 Xiaofei Qi , Jinchuan Hou

Witnessing entanglement is crucial in quantum information processing. With properly preparing ancillary states, it has been shown previously that genuine entanglement can be witnessed without trusting measurement devices. In this work, we…

Quantum Physics · Physics 2016-07-28 Qi Zhao , Xiao Yuan , Xiongfeng Ma

Entanglement is one of the most prominent features of quantum mechanics and serves as an essential resource in quantum information science. Therefore, the certification of entanglement is crucial for quantum information processing tasks.…

Quantum Physics · Physics 2025-04-10 Jing-Tao Qiu , Wei-Jie Jiang , Xiao-Dong Yu

We introduce a sequence of numerical tests that can determine the entanglement or separability of a state even when there is not enough information to completely determine its density matrix. Given partial information about the state in the…

Quantum Physics · Physics 2012-12-14 Federico M. Spedalieri

In this work, we present a practical and efficient framework for verifying entangled states when only a tomographically incomplete measurement setting is available-specifically, when access to observables is severely limited. We show how…

Entanglement witnesses (EWs) are a versatile tool to detect entangled states and characterize related properties of entanglement in quantum information theory. A witness $W$ corresponds to an observable satisfying…

Quantum Physics · Physics 2026-01-19 Jiheon Seong , Anindita Bera , Beatrix C. Hiesmayr , Dariusz Chruscinski , Joonwoo Bae

We present an unifying approach to the quantification of entanglement based on entanglement witnesses, which includes several already established entanglement measures such as the negativity, the concurrence and the robustness of…

Quantum Physics · Physics 2007-05-23 Fernando Guadalupe Santos Lins Brandao

The generation and verification of large-scale entanglement are essential to the development of quantum technologies. In this paper, we present an efficient scheme to generate genuine multipartite entanglement of a large number of qubits by…

Quantum Physics · Physics 2021-06-02 Yihong Zhang , Yifan Tang , You Zhou , Xiongfeng Ma

We study the optimal entanglement witness with respect to multiqubits W-states. We show such entanglement witnesses can be used to distinguish genuine entangled states, different biseparable states and fully separable states.

Quantum Physics · Physics 2015-05-13 Ming-Jing Zhao , Zhi-Xi Wang , Shao-Ming Fei

There always exists an entanglement witness for every entangled quantum state. Negativity of the expectation value of an entanglement witness operator guarantees entanglement of the corresponding state, given that the measurement devices…

Quantum Physics · Physics 2021-03-24 Kornikar Sen , Chirag Srivastava , Shiladitya Mal , Aditi Sen De , Ujjwal Sen

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