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Quantifying quantum coherence is a key task in the resource theory of coherence. Here we establish a good coherence monotone in terms of a state conversion process, which automatically endows the coherence monotone with an operational…

Quantum Physics · Physics 2020-07-01 Deng-hui Yu , Li-qiang Zhang , Chang-shui Yu

Quantum metrology concerns improving the estimation of an unknown parameter using an optimal measurement scheme on the quantum system. More the optimality of the measurement, the better will be the improvement in sensing the value of the…

Quantum Physics · Physics 2025-07-30 H. S. Karthik

Spin anticoherent states acquired recently a lot of attention as the most "quantum" states. Some coherent and anticoherent spin states are known as optimal quantum rotosensors. In this work, we introduce a measure of quantumness for…

Quantum Physics · Physics 2024-01-31 Marcin Rudziński , Adam Burchardt , Karol Życzkowski

A long-standing problem in quantum physics is to determine the minimal number of measurement bases required for the complete characterization of unknown quantum states, a question of particular relevance to high-dimensional quantum…

Quantum Physics · Physics 2025-08-12 Tianqi Xiao , Yaxin Wang , Ying Xia , Zhihao Li , Xiaoqi Zhou

We investigate the performance of discrimination strategy in the comparison task of known quantum states. In the discrimination strategy, one infers whether or not two quantum systems are in the same state on the basis of the outcomes of…

Quantum Physics · Physics 2018-05-30 A. Hayashi , T. Hashimoto , M. Horibe

We study quantum state testing where the goal is to test whether $\rho=\rho_0\in\mathbb{C}^{d\times d}$ or $\|\rho-\rho_0\|_1>\varepsilon$, given $n$ copies of $\rho$ and a known state description $\rho_0$. In practice, not all measurements…

Quantum Physics · Physics 2024-09-02 Yuhan Liu , Jayadev Acharya

We investigate how to determine whether the states of a set of quantum systems are identical or not. This paper treats both error-free comparison, and comparison where errors in the result are allowed. Error-free comparison means that we…

Quantum Physics · Physics 2015-06-26 Igor Jex , Erika Andersson , Anthony Chefles

We introduce a reliable compressive procedure to uniquely characterize any given low-rank quantum measurement using a minimal set of probe states that is based solely on data collected from the unknown measurement itself. The procedure is…

Quantum Physics · Physics 2020-11-03 I. Gianani , Y. S. Teo , V. Cimini , H. Jeong , G. Leuchs , M. Barbieri , L. L. Sanchez-Soto

We address the problem of unambiguously identifying the state of a probe qudit with the state of one of d reference qudits. The reference states are assumed pure and linearly independent but we have no knowledge of them. The state of the…

Quantum Physics · Physics 2009-11-13 Ulrike Herzog , Janos A. Bergou

With the advance of quantum information technology, the question of how to most efficiently test quantum circuits is becoming of increasing relevance. Here we introduce the statistics of lengths of measurement sequences that allows one to…

Quantum Physics · Physics 2022-10-27 N. Milazzo , D. Braun , O. Giraud

Quantum coherence characterizes the non-classical feature of a single party system with respect to a local basis. Based on a recently introduced resource framework, coherence can be regarded as a resource and be systematically manipulated…

Quantum Physics · Physics 2018-09-26 Yunchao Liu , Qi Zhao , Xiao Yuan

We derive the optimal measurement for quantum state discrimination without a priori probabilities, i.e. in a minimax strategy instead of the usually considered Bayesian one. We consider both minimal-error and unambiguous discrimination…

Quantum Physics · Physics 2025-04-02 Giacomo Mauro D'Ariano , Massimiliano Federico Sacchi , Jonas Kahn

We study the average quantum coherence over the pure state decompositions of a mixed quantum state. An upper bound of the average quantum coherence is provided and sufficient conditions for the saturation of the upper bound are shown. These…

Quantum Physics · Physics 2021-05-07 Ming-Jing Zhao , Teng Ma , Rajesh Pereira

A long standing problem in quantum mechanics is the minimum number of observables required for the characterisation of unknown pure quantum states. The solution to this problem is specially important for the developing field of…

Quantum Physics · Physics 2015-09-02 D. Goyeneche , G. Cañas , S. Etcheverry , E. S. Gómez , G. B. Xavier , G. Lima , A. Delgado

We identify the optimal measurement for obtaining information about the original quantum state after the state to be measured has undergone partial decoherence due to noise. We quantify the information that can be obtained by the…

Quantum Physics · Physics 2010-01-15 Yu Watanabe , Takahiro Sagawa , Masahito Ueda

We introduce a new method to estimate unknown pure $d$-dimensional quantum states using the probability distributions associated with only three measurement bases. Measurement results of $2d$ projectors are employed to generate a set of…

Quantum Physics · Physics 2020-06-08 L. Zambrano , L. Pereira , D. Martínez , G. Cañas , G. Lima , A. Delgado

We describe an optimized, self-correcting procedure for the Bayesian inference of pure quantum states. By analyzing the history of measurement outcomes at each step, the procedure returns the most likely pure state, as well as the optimal…

Quantum Physics · Physics 2015-09-14 Amir Kalev , Itay Hen

Mutually unbiased bases determine an optimal set of measurements to extract complete information about the quantum state of a system. However, quite often a priori information about the state exist, making some of the measurement bases…

Quantum Physics · Physics 2015-06-12 A. B. Klimov , G. Bjork , L. L. Sanchez-Soto

Coherence is a defining property of quantum theory that accounts for quantum advantage in many quantum information tasks. Although many coherence quantifiers have been introduced in various contexts, the lack of efficient methods to…

Quantum Physics · Physics 2023-01-02 Sun Liang Liang , Yu Sixia

We consider realistic measurement systems, where measurements are accompanied by decoherence processes. The aim of this work is the construction of methods and algorithms for precise quantum measurements with fidelity close to the…

Quantum Physics · Physics 2017-01-10 Yu. I. Bogdanov , B. I. Bantysh , N. A. Bogdanova , A. B. Kvasnyy , V. F. Lukichev