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We propose an entanglement criterion based on local uncertainty relations (LURs) in a stronger form than the original LUR criterion introduced in [H. F. Hofmann and S. Takeuchi, Phys. Rev. A \textbf{68}, 032103 (2003)]. Using arbitrarily…

Quantum Physics · Physics 2015-05-14 Cheng-Jie Zhang , Hyunchul Nha , Yong-Sheng Zhang , Guang-Can Guo

We elucidate the requirements for quantum operations that achieve environment-assisted invariance (envariance), a symmetry of entanglement. While envariance has traditionally been studied within the framework of local unitary operations, we…

Quantum Physics · Physics 2025-06-25 Akira Sone , Akram Touil , Kenji Maeda , Paola Cappellaro , Sebastian Deffner

We consider the transformation of Hamilton operators under various sets of quantum operations acting simultaneously on all adjacent pairs of particles. We find mappings between Hamilton operators analogous to duality transformations as well…

Quantum Physics · Physics 2015-06-26 Martin B Plenio

We introduce a class of inequalities based on low order correlations of operators to detect entanglement in bipartite systems. The operators may either be Hermitian or non-Hermitian and are applicable to any physical system or class of…

Quantum Physics · Physics 2019-10-02 Yumang Jing , Qiongyi He , Tim Byrnes

We construct entanglement witnesses using fundamental quantum operators of spin models which contain two-particle interactions and posses a certain symmetry. By choosing the Hamiltonian as such an operator, our method can be used for…

Quantum Physics · Physics 2016-01-29 Geza Toth

There have been numerous studies of entanglement in spin systems. These have usually focussed on examining the entanglement between individual spins or determining whether the state of the system is completely separable. Here we present…

Quantum Physics · Physics 2015-05-19 Hongjun Zheng , Ho Trung Dung , Mark Hillery

We examine in $(2+1)$-dimensional anti-de Sitter (AdS) space the phenomena of entanglement harvesting - the process in which a pair of detectors (two-level atoms) extract entanglement from a quantum field through local interactions with the…

We formulate an entanglement criterion using Peres-Horodecki positive partial transpose operations combined with the Schr\"odinger-Robertson uncertainty relation. We show that any pure entangled bipartite and tripartite state can be…

Quantum Physics · Physics 2009-11-13 J. Gillet , T. Bastin , G. S. Agarwal

Currently available separability criteria for continuous-variable states are generally based on the covariance matrix of quadrature operators. The well-known separability criterion of Duan et al. [Phys. Rev. Lett. 84, 2722 (2000)] and Simon…

Quantum Physics · Physics 2016-03-24 Anaelle Hertz , Evgueni Karpov , Aikaterini Mandilara , Nicolas J. Cerf

We study the half system entanglement Hamiltonians of the ground state of free fermion critical transverse field Ising model with periodic boundary conditions in the presence of defects. In general, we observe that these defects introduce…

Quantum Physics · Physics 2025-06-05 Gavin Rockwood

The conditional shift in the evolution operator of a quantum walk generates entanglement between the coin and position degrees of freedom. This entanglement can be quantified by the von Neumann entropy of the reduced density operator…

Quantum Physics · Physics 2009-11-11 G. Abal , R. Siri , A. Romanelli , R. Donangelo

Entanglement is a key resource for quantum information technologies ranging from quantum sensing to quantum computing. Conventionally, the entanglement between two coupled qubits is established at the time scale of the inverse of the…

Quantum Physics · Physics 2023-09-12 Zeng-Zhao Li , Weijian Chen , Maryam Abbasi , Kater W. Murch , K. Birgitta Whaley

In a recent paper (arXiv:1905.07348v1), Dyson scheme to deal with density matrix of non-Hermitian Hamiltonians has been used to investigate the entanglement of states of a PT-symmetric bosonic system. They found that von Neumann entropy can…

Quantum Physics · Physics 2020-10-20 C. A. Goulart , M. P. Pato

We derive conditions in the form of inequalities to detect the genuine $N$-partite entanglement of $N$ systems. The inequalities are expressed in terms of variances of spin operators, and can be tested by local spin measurements performed…

Quantum Physics · Physics 2020-09-24 R. Y. Teh , M. D. Reid

Entanglement is studied in the framework of Dyson's S-matrix theory in relativistic quantum field theory, which leads to a natural definition of entangled states of a particle-antiparticle pair and the spin operator from a Noether current.…

Quantum Physics · Physics 2015-06-18 Kazuo Fujikawa , C. H. Oh , Chengjie Zhang

We present several entanglement conditions in order to detect bound entangled states in continuous variable systems. Specifically, Werner and Wolf [Phys. Rev. Lett. 86, 3658 (2001)] and Horodecki and Lewenstein [Phys. Rev. Lett. 85, 2657…

Quantum Physics · Physics 2015-05-19 Cheng-Jie Zhang , Hyunchul Nha , Yong-Sheng Zhang , Guang-Can Guo

In the usual entanglement detection scenario the possible measurements and the corresponding data are assumed to be fully characterized. We consider the situation where the measurements are known, but the data is scrambled, meaning the…

Quantum Physics · Physics 2019-07-01 Timo Simnacher , Nikolai Wyderka , René Schwonnek , Otfried Gühne

We introduce a general framework for detecting genuine multipartite entanglement and non full-separability in multipartite quantum systems of arbitrary dimensions based on correlation tensors. Regarding genuine multipartite entanglement our…

Quantum Physics · Physics 2011-12-08 Julio I. de Vicente , Marcus Huber

We present a class of entanglement identifiers which has the following experimentally friendly feature: once the expectation value of the identifier exceeds some definite limit, we can conclude the state is entangled, even if not all…

Quantum Physics · Physics 2013-08-22 Wieslaw Laskowski , Marcin Markiewicz , Tomasz Paterek , Ryszard Weinar

We consider physical Hamiltonians that can be represented by the multiparametric Gaussian ensembles, theoretically derive the state ensembles for its eigenstates and analyze the effect of varying system conditions on its bipartite…

Quantum Physics · Physics 2026-04-14 Devanshu Shekhar , Pragya Shukla