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Entanglement and its propagation are central to understanding a multitude of physical properties of quantum systems. Notably, within closed quantum many-body systems, entanglement is believed to yield emergent thermodynamic behavior.…

We propose new entanglement measures as the detection performance based on the hypothesis testing setting. We clarify how our measures work for detecting an entangled state by extending the quantum Sanov theorem. Our analysis covers the…

Quantum Physics · Physics 2025-01-08 Masahito Hayashi , Yuki Ito

I give an overview of some of the most used measures of entanglement. To make the presentation self-contained, a number of concepts from quantum information theory are first explained. Then the structure of bipartite entanglement is studied…

Quantum Physics · Physics 2007-05-23 Geir Ove Myhr

In the quest of completely describing entanglement in the general case of a finite number of parties sharing a physical system of finite dimensional Hilbert space a new entanglement magnitude is introduced for its pure and mixed states:…

Quantum Physics · Physics 2009-10-31 Guifre Vidal , Rolf Tarrach

This paper presents a new measure of entanglement which can be employed for multipartite entangled systems. The classification of multipartite entangled systems based on this measure is considered. Two approaches to applying this measure to…

Quantum Physics · Physics 2018-08-20 Seyed Arash Sheikholeslam , Thomas Aaron Gulliver

Among the many facets of quantum correlations, bound entanglement has remained one the most enigmatic phenomena, despite the fact that it was discovered in the early days of quantum information. Even its detection has proven to be…

Quantum Physics · Physics 2016-09-07 Gael Sentís , Christopher Eltschka , Jens Siewert

A simple two-qubit model showing Quantum Phase Transitions as a consequence of ground state level crossings is studied in detail. Using the Concurrence of the system as an entanglement measure and heat capacity as a marker of…

Quantum Physics · Physics 2011-04-07 B. Leggio , A. Napoli , H. Nakazato , A. Messina

We introduce an experimental procedure for the detection of quantum entanglement of an unknown quantum state with as few measurements as possible. The method requires neither a priori knowledge of the state nor a shared reference frame…

We investigate the creation of highly entangled ground states in a system of three exchange-coupled qubits arranged in a ring geometry. Suitable magnetic field configurations yielding approximate GHZ and exact W ground states are…

Quantum Physics · Physics 2008-03-19 Beat Röthlisberger , Jörg Lehmann , D. S. Saraga , Philipp Traber , Daniel Loss

We produce and holographically measure entangled qudits encoded in transverse spatial modes of single photons. With the novel use of a quantum state tomography method that only requires two-state superpositions, we achieve the most complete…

The quantum entanglement measure is determined, for the first time, for antiferromagnetic trimer spin-1/2 Heisenberg chains. The physical quantity proposed to measure the entanglement is the distance between states by adopting the…

Quantum Physics · Physics 2015-04-14 O. M. Del Cima , D. H. T. Franco , S. L. L. da Silva

When a multi-qubit state evolves under local unitaries it may obtain a geometric phase, a feature dependent on the geometry of the state's projective Hilbert space. A correction term to this geometric phase in addition to the local…

Quantum Physics · Physics 2010-05-12 Mark S. Williamson , Vlatko Vedral

It is a specific type of quantum correlated state that achieves optimal precision in parameterestimation under unitary encoding. We consider the potential experimental limitation on probe entanglement, and find a relation between achievable…

Quantum Physics · Physics 2026-01-06 Debarupa Saha , Ujjwal Sen

By calculating entanglement measures and quantum violation of Bell-type inequality, we reveal the relationship between entanglement measure and the amount of quantum violation for a family of four-qubit entangled states. It has been…

Quantum Physics · Physics 2017-06-07 Dong Ding , Yingqiu He , Fengli Yan , Ting Gao

Several entanglement measures are used to define equivalence classes in the set of hypergraph states of three qubits. Our classifications reveal that (i) under local unitary transformations, hypergraph states of three qubits are split into…

Quantum Physics · Physics 2013-04-24 Ri Qu , Zong-shang Li , Juan Wang , Yan-ru Bao

Similar to the three-qubit Greenberger-Horne-Zeilinger (GHZ) symmetry we explore the four-qubit GHZ symmetry group and its subgroup called restricted GHZ symmetry group. While the set of symmetric states under the whole group transformation…

Quantum Physics · Physics 2015-06-15 DaeKil Park

Our investigation aims to study the specific role played by entanglement in the quantum computation process, by elaborating an entangled spin model developed within the 'hidden measurement approach' to quantum mechanics. We show that an…

Quantum Physics · Physics 2007-05-23 Diederik Aerts , Ellie D'Hondt , Bart D'Hooghe

Quantum entanglement is a key resource in quantum computing and quantum information processing tasks. However, its quantification remains a major challenge since it cannot be directly extracted from physical observables. To address this…

Quantum Physics · Physics 2025-12-29 Shruti Aggarwal , Trasha Gupta , R. K. Agrawal , S. Indu

In this paper we are focusing on entanglement control problem in a three-qubit system. We demonstrate that vector representation of entanglement, associated with SO(6) representation of SU(4) two-qubit group, can be used to solve various…

Quantum Physics · Physics 2024-03-05 Dmitry B. Uskov , Paul M. Alsing

Entanglement is a fundamental feature of quantum mechanics and holds great promise for enhancing metrology and communications. Much of the focus of quantum metrology so far has been on generating highly entangled quantum states that offer…