English
Related papers

Related papers: A New Relation between post and pre-optimal measur…

200 papers

We investigate the optimal approximation to triple incompatible quantum measurements within the framework of statistical distance and joint measurability. According to the lower bound of the uncertainty inequality presented in [Physical…

Quantum Physics · Physics 2022-06-01 Hui-Hui Qin , Shao-Ming Fei

We analyze entropic uncertainty relations in a finite dimensional Hilbert space and derive several strong bounds for the sum of two entropies obtained in projective measurements with respect to any two orthogonal bases. We improve the…

Quantum Physics · Physics 2015-06-30 Łukasz Rudnicki , Zbigniew Puchała , Karol Życzkowski

We report on experimental measurement of the Hilbert-Schmidt distance between two two-qubit states by many-particle interference. We demonstrate that our three-step method for measuring distances in Hilbert space is far less complex than…

Quantum Physics · Physics 2021-12-28 Vojtěch Trávníček , Karol Bartkiewicz , Antonín Černoch , Karel Lemr

Bounds analogous to entropic uncertainty relations allow one to design practical tests to detect quantum entanglement by a collective measurement performed on several copies of the state analyzed. This approach, initially worked out for…

Quantum Physics · Physics 2013-01-04 Łukasz Rudnicki , Zbigniew Puchała , Paweł Horodecki , Karol Życzkowski

In standard formulations of the uncertainty principle, two fundamental features are typically cast as impossibility statements: two noncommuting observables cannot in general both be sharply defined (for the same state), nor can they be…

Quantum Physics · Physics 2018-06-08 Tom Bullock , Paul Busch

Fidelity is the standard measure for quantifying the similarity between two quantum states. It is equal to the square of the minimum Bhattacharyya coefficient between the probability distributions induced by quantum measurements on the two…

Quantum Physics · Physics 2025-12-01 Datong Chen , Huangjun Zhu

Majorization uncertainty relations are generalized for an arbitrary mixed quantum state $\rho$ of a finite size $N$. In particular, a lower bound for the sum of two entropies characterizing probability distributions corresponding to…

Quantum Physics · Physics 2018-04-17 Zbigniew Puchała , Łukasz Rudnicki , Aleksandra Krawiec , Karol Życzkowski

The uncertainty relation lies at the heart of quantum theory and behaves as a non-classical constraint on the indeterminacies of incompatible observables in a system. In the literature, many experiments have been devoted to the test of the…

Quantum Physics · Physics 2022-04-20 Shuang Wang , Fang-Xia Meng , Hui Wang , Cong-Feng Qiao

The connection between maximal sets of mutually unbiased bases (MUBs) in a prime-power dimensional Hilbert space and finite phase-space geometries is well known. In this article we classify MUBs according to their degree of covariance with…

Mathematical Physics · Physics 2016-06-23 Claudio Carmeli , Jussi Schultz , Alessandro Toigo

Mixture models, such as Gaussian mixture models, are widely used in machine learning to represent complex data distributions. A key challenge, especially in high-dimensional settings, is to determine the mixture order and estimate the…

Optimization and Control · Mathematics 2025-09-30 Srećko Đurašinović , Jean-Bernard Lasserre , Victor Magron

We present the optimal measurement strategy for distinguishing between three quantum states exhibiting a mirror symmetry. The three states live in a two-dimensional Hilbert space, and are thus overcomplete. By mirror symmetry we understand…

Quantum Physics · Physics 2009-11-07 Erika Andersson , Stephen M. Barnett , Claire R. Gilson , Kieran Hunter

Quantum measurements based on mutually unbiased bases (MUB) play crucial roles in foundational studies and quantum information processing. It is known that there exist inequivalent MUB, but little is known about their operational…

Quantum Physics · Physics 2023-11-14 Wen-Zhe Yan , Yunting Li , Zhibo Hou , Huangjun Zhu , Guo-Yong Xiang , Chuan-Feng Li , Guang-Can Guo

The optimal (pure state) ensemble length of a separable state, A, is the minimum number of (pure) product states needed in convex combination to construct A. We study the set of all separable states with optimal (pure state) ensemble length…

Quantum Physics · Physics 2015-06-26 Robert B. Lockhart

We study an optimum measurement for quantum state discrimination, which maximizes the probability of correct results when the probability of inconclusive results is fixed at a given value. The measurement describes minimum-error…

Quantum Physics · Physics 2012-09-26 Ulrike Herzog

We examine, in correlated mixed states of qudit-qubit systems, the set of all conditional qubit states that can be reached after local measurements at the qudit based on rank-1 projectors. While for a similar measurement at the qubit, the…

Quantum Physics · Physics 2019-07-03 M. Bilkis , N. Canosa , R. Rossignoli , N. Gigena

We study the problem of performing orthogonal qubit measurements simultaneously. Since these measurements are incompatible, one has to accept additional imprecision. An optimal joint measurement is the one with the least possible…

Quantum Physics · Physics 2010-10-12 Teiko Heinosaari , Maria Anastasia Jivulescu , Daniel Reitzner , Mario Ziman

We propose a scheme for engineering compressed spatial states in a two-dimensional parabolic potential with a spin-orbit coupling by selective spin measurements. This sequence of measurements results in a coordinate-dependent density matrix…

Other Condensed Matter · Physics 2016-12-14 P. V. Pyshkin , E. Ya. Sherman , Da-Wei Luo , J. Q. You , Lian-Ao Wu

We analyze the optimal measurements accessing classical correlations in arbitrary two-qubit states. Two-qubit states can be transformed into the canonical forms via local unitary operations. For the canonical forms, we investigate the…

Quantum Physics · Physics 2011-02-09 Xiao-Ming Lu , Jian Ma , Zhengjun Xi , Xiaoguang Wang

We discuss what can be inferred from measurements on one- and two-qubit systems using a single measurement basis at various times. We show that, given reasonable physical assumptions, carrying out such measurements at quarter-period…

Quantum Physics · Physics 2010-08-23 Bella Schelpe , Adrian Kent , William Munro , Tim Spiller

Maximally entangled mixed states are those states that, for a given mixedness, achieve the greatest possible entanglement. For two-qubit systems and for various combinations of entanglement and mixedness measures, the form of the…