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Tripartite entangled states, such as GHZ and W states, are typically generated by manipulating two pairs of polarization-entangled photons in bulk optics. Here we propose a scheme to generate W states that are entangled in the energy degree…

Quantum Physics · Physics 2016-08-03 M. Menotti , L. Maccone , J. E. Sipe , M. Liscidini

Based on total variance of a pair of Einstein-Podolsky-Rosen (EPR) type operators, the generalized EPR entangled states in continuous variable systems are defined. We show that such entangled states must correspond with two-mode squeezing…

Quantum Physics · Physics 2009-11-10 Yun-Jie Xia , Guang-Can Guo

We argue that holographic CFT states require a large amount of tripartite entanglement, in contrast to the conjecture that their entanglement is mostly bipartite. Our evidence is that this mostly-bipartite conjecture is in sharp conflict…

High Energy Physics - Theory · Physics 2020-05-20 Chris Akers , Pratik Rath

Non-Hermitian quantum systems showcase many distinct and intriguing features with no Hermitian counterparts. One of them is the exceptional point which marks the PT (parity and time) symmetry phase transition, where an enhanced spectral…

Quantum Physics · Physics 2025-03-28 C. -Y. Liu , C. G. Feyisa , Muhammad S. Hasan , H. H. Jen

Despite the fundamental importance of quantum entanglement in many-body systems, our understanding is mostly limited to bipartite situations. Indeed, even defining appropriate notions of multipartite entanglement is a significant challenge…

Quantum Physics · Physics 2021-01-15 Sepehr Nezami , Michael Walter

Genuine high-dimensional entanglement, i.e. the property of having a high Schmidt number, constitutes a resource in quantum communication, overcoming limitations of low-dimensional systems. States with a positive partial transpose (PPT), on…

Quantum Physics · Physics 2018-11-21 Marcus Huber , Ludovico Lami , Cécilia Lancien , Alexander Müller-Hermes

Among the most fundamental questions in the manipulation of quantum resources such as entanglement is the possibility of reversibly transforming all resource states. The key consequence of this would be the identification of a unique…

Quantum Physics · Physics 2024-04-18 Bartosz Regula , Ludovico Lami

The discovery of entangled quantum states from which one cannot distill pure entanglement constitutes a fundamental recent advance in the field of quantum information. Such bipartite bound-entangled (BE) quantum states \emph{could} fall…

Quantum Physics · Physics 2009-11-10 Somshubhro Bandyopadhyay , Vwani Roychowdhury

Recently, it has been shown that locally randomized measurements can be employed to get partial transpose moments of a density matrix [Elben A., {\it et al.} Phys. Rev. Lett. {\bf 125}, 200501 (2020)]. Consequently, two general entanglement…

Quantum Physics · Physics 2023-05-16 Mazhar Ali

We study bipartite entangled states in arbitrary dimensions and obtain different bounds for the entanglement measures in terms of teleportation fidelity. We find that there is a simple relation between negativity and teleportation fidelity…

Quantum Physics · Physics 2014-03-12 Sk. Sazim , Satyabrata Adhikari , Subhashish Banerjee , T. Pramanik

Maximally entangled states are of utmost importance to quantum communication, dense coding, and quantum teleportation. With a trapped ion placed inside a high finesse optical cavity, interacting with field of an external laser and quantized…

Quantum Physics · Physics 2009-11-11 S. Shelly Sharma , N. K. Sharma

A novel use of Majorana geometric representation brings out distinct entanglement families of permutation symmetric states of qubits. The paradigmatic W and GHZ (Greenberger-Horne-Zeilinger) states of three qubits respectively contain two…

Quantum Physics · Physics 2010-02-16 A R Usha Devi , Sudha , A K Rajagopal

Multiqubit positive-partial-transpose (PPT) entangled states play an important role in quantum information theory. We characterize such states of minimum rank in three-qubit system, namely rank four. Depending on whether the Lorentz…

Quantum Physics · Physics 2026-05-20 Yonggang Cheng , Lin Chen

We analyze entanglement and nonlocal properties of the convex set of symmetric $N$-qubits states which are diagonal in the Dicke basis. First, we demonstrate that within this set, positivity of partial transposition (PPT) is necessary and…

Quantum Physics · Physics 2017-05-03 Ruben Quesada , Swapan Rana , Anna Sanpera

We implemented a triply entangled Greenberger-Horne-Zeilinger(GHZ)-like state and coherently manipulated the spin, path, and energy degrees of freedom in a single neutron system. The GHZ-like state was analyzed with an inequality derived by…

Quantum Physics · Physics 2015-05-13 Yuji Hasegawa , Rudolf Loidl , Gerald Badurek , Stephan Sponar , Helmut Rauch

Quantifying the minimum entanglement needed to prepare quantum states and implement quantum processes is a key challenge in quantum information theory. In this work, we develop computable and faithful lower bounds on the entanglement cost…

Quantum Physics · Physics 2025-05-08 Xin Wang , Mingrui Jing , Chengkai Zhu

Generic high-dimensional bipartite pure states are overwhelmingly likely to be highly entangled. Remarkably, this ubiquitous phenomenon can already arise in finite-dimensional systems. However, unlike the bipartite setting, the entanglement…

Quantum Physics · Physics 2026-01-15 Mu-En Liu , Kai-Siang Chen , Chung-Yun Hsieh , Gelo Noel M. Tabia , Yeong-Cherng Liang

We introduce a new class of multipartite entangled mixed states with pure state decompositions of generalized W states, similar to Schmidt-correlated states having generalized GHZ states in the pure state decomposition. The entanglement and…

Quantum Physics · Physics 2010-12-20 Ming-Jing Zhao , Shao-Ming Fei , Zhi-Xi Wang

Positivity of the density operator reflects itself in terms of sequences of inequalities on observable moments. Uncertainty relations for non-commuting observables form a subset of these inequalities. In addition, criterion of positivity…

Quantum Physics · Physics 2008-12-21 A R Usha Devi , A K Rajagopal

We investigate three superconducting flux qubits coupled in a loop. In this setup, tripartite entanglement can be created in a natural, controllable, and stable way. Both generic kinds of tripartite entanglement -the W type as well as the…

Quantum Physics · Physics 2015-05-14 Johannes Ferber , Frank K. Wilhelm