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In this study the determinant of the average quadratic error matrix is used as the measure of state estimation efficiency. This quantity is easily computable in some cases, so it gives us a reasonable tool to find optimal measurement setup…

Quantum Physics · Physics 2012-01-10 Denes Petz , Laszlo Ruppert

Competing orders is a general concept to describe various quantum phases and transitions in various materials. One efficient way to investigate competing orders is to first classify different class of excitations in a given quantum phase,…

Strongly Correlated Electrons · Physics 2016-07-13 Fadi Sun , Jinwu Ye , Wu-Ming Liu

We present the first complete optimization of quantum tomography, for states, POVMs, and various classes of transformations, for arbitrary prior ensemble and arbitrary representation, giving corresponding feasible experimental schemes.

Quantum Physics · Physics 2009-11-13 A. Bisio , G. Chiribella , G. M. D'Ariano , S. Facchini , P. Perinotti

We study the geometric measure of entanglement (GM) of pure symmetric states related to rank-one positive-operator-valued measures (POVMs) and establish a general connection with quantum state estimation theory, especially the maximum…

Quantum Physics · Physics 2011-01-17 Lin Chen , Huangjun Zhu , Tzu-Chieh Wei

Recently, a novel framework for semi-device-independent quantum prepare-and-measure protocols has been proposed, based on the assumption of a limited distinguishability between the prepared quantum states. Here, we discuss the problem of…

Quantum Physics · Physics 2019-11-11 Weixu Shi , Yu Cai , Jonatan Bohr Brask , Hugo Zbinden , Nicolas Brunner

We discuss the problem of implementing generalized measurements (POVMs) with linear optics, either based upon a static linear array or including conditional dynamics. In our approach, a given POVM shall be identified as a solution to an…

Quantum Physics · Physics 2016-08-16 Peter van Loock , Kae Nemoto , William J. Munro , Philippe Raynal , Norbert Lütkenhaus

We present a way of experimentally determining the concurrence in terms of the expectation values of local observables for arbitrary multipartite pure states. In stead of the joint measurements on two copies of a state in the experiment for…

Quantum Physics · Physics 2015-05-14 Shao-Ming Fei , Ming-Jing Zhao , Kai Chen , Zhi-Xi Wang

Among certification techniques, those based on the violation of Bell inequalities are appealing because they do not require assumptions on the underlying Hilbert space dimension and on the accuracy of calibration methods. Such…

Quantum Physics · Physics 2020-03-20 Sebastian Wagner , Jean-Daniel Bancal , Nicolas Sangouard , Pavel Sekatski

We construct an entanglement measure that coincides with the generalized concurrence for a general pure bipartite state based on wedge product. Moreover, we construct an entanglement measure for pure multi-qubit states, which are…

Quantum Physics · Physics 2007-05-23 Hoshang Heydari

Quantum state tomography seeks to reconstruct an unknown state from measurement statistics. A finite measurement (POVM) is \emph{pure-state informationally complete} (PSI-Complete) if the outcome probabilities determine any pure state up to…

Quantum Physics · Physics 2025-11-13 Dan Edidin , Ivan Gonzalez , Itzhak Tamo

We show that, for any composite system with an arbitrary number of finite-dimensional subsystems, it is possible to directly measure the multipartite concurrence of pure states by detecting only one single factorizable observable, provided…

Quantum Physics · Physics 2009-11-13 Leandro Aolita , Florian Mintert

The objective of this work is to develop a recursive, discrete time quantum filtering equation for a system that interacts with a probe, on which measurements are performed according to the Positive Operator Valued Measures (POVMs)…

Quantum Physics · Physics 2013-09-10 Ram A. Somaraju , Alain Sarlette , Hugo Thienpont

Since entanglement is not an observable per se, measuring its value in practice is a difficult task. Here we propose a protocol for quantifying a particular entanglement measure, namely concurrence, of an arbitrary two-qubit pure state via…

Quantum Physics · Physics 2017-05-10 Mikko Tukiainen , Hirokazu Kobayashi , Yutaka Shikano

Device-independent (DI) quantum protocols exploit Bell inequality violations to ensure security or certify quantum properties without making assumptions about the internal workings of the devices. In this work, we study the role of rank-one…

The geometry of the Quantum State Space, described by Bloch vectors, is a very intricate one. A deeper understanding of this geometry could lead to the solution of some difficult problems in Quantum Foundations and Quantum Information such…

Quantum Physics · Physics 2013-09-30 Jose Ignacio Rosado

We present quantum-inspired algorithms for classification tasks inspired by the problem of quantum state discrimination. By construction, these algorithms can perform multiclass classification, prevent overfitting, and generate probability…

Quantum Physics · Physics 2023-03-28 Emmanuel Zambrini Cruzeiro , Christine De Mol , Serge Massar , Stefano Pironio

Determining the conditions under which positive operator-valued measures (POVMs), the most general class of quantum measurements, outperform projective measurements remains a challenging and largely unresolved problem. Of particular…

Quantum multipartite entangled states play significant roles in quantum information processing. By using difference schemes and orthogonal partitions, we construct a series of infinite classes of irredundant mixed orthogonal arrays (IrMOAs)…

Quantum Physics · Physics 2021-05-04 Shanqi Pang , Xiao Zhang , Shao-Ming Fei , Zhu-Jun Zheng

Motivated by quantum resource theories, we introduce a notion of incompatibility for quantum measurements relative to a reference basis. The notion arises by considering states diagonal in that basis and investigating whether probability…

Quantum Physics · Physics 2019-08-21 Georgios Styliaris , Paolo Zanardi

We develop a unified, information theoretic interpretation of the number-phase complementarity that is applicable both to finite-dimensional (atomic) and infinite-dimensional (oscillator) systems, with number treated as a discrete Hermitian…

Quantum Physics · Physics 2015-05-13 Subhashish Banerjee , R. Srikanth