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We present an experimental implementation of optimum measurements for quantum state discrimination. Optimum maximum-confidence discrimination and optimum unambiguous discrimination of two mixed single-photon polarization states were…

Given two sets finite $S_0$ and $S_1$ of quantum states. We show necessary and sufficient conditions for distinguishing them by a measurement.

Quantum Physics · Physics 2007-05-23 Rahul Jain

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

The separability detecting problem of mixed states is one of the fundamental problems in quantum information theory. In the last 20 years, almost all methods are based on the sufficient or necessary conditions for entanglement. However, in…

Quantum Physics · Physics 2020-07-15 Ying Li , Guyan Ni

We introduce a quantity called the coherence of purification which can be a measure of total quantumness for a single system. We prove that coherence of purification is always more than the coherence of the system. For a pure state, the…

Quantum Physics · Physics 2019-07-31 Arun Kumar Pati , Long-Mei Yang , Chiranjib Mukhopadhyay , Shao-Ming Fei , Zhi-Xi Wang

In this study, we investigate the problem of determining the maximum purity for absolutely separable and absolutely PPT quantum states. From the geometric viewpoint, this problem is equivalent to asking for the exact Euclidean radius of the…

Mathematical Physics · Physics 2025-10-23 Hoang Phi Dung , Vu The Khoi

We address the following state comparison problem: is it possible to design an experiment enabling us to unambiguously decide (based on the observed outcome statistics) on the sameness or difference of two unknown state preparations without…

Quantum Physics · Physics 2012-06-05 Sergey N. Filippov , Mario Ziman

The quantum discrimination of two non-coherent states draws much attention recently. In this letter, we first consider the quantum discrimination of two noiseless displaced number states. Then we derive the Fock representation of noisy…

Quantum Physics · Physics 2020-12-10 Renzhi Yuan , Julian Cheng

The resource theory of quantum coherence studies the off-diagonal elements of a density matrix in a distinguished basis, whereas the resource theory of purity studies all deviations from the maximally mixed state. We establish a direct…

Quantum Physics · Physics 2018-06-05 Alexander Streltsov , Hermann Kampermann , Sabine Wölk , Manuel Gessner , Dagmar Bruß

The estimation of the density matrix of a $k$-level quantum system is studied when the parametrization is given by the real and imaginary part of the entries and they are estimated by independent measurements. It is established that the…

Quantum Physics · Physics 2009-11-13 D. Petz , K. M. Hangos , A. Magyar

In this paper we consider the optimal discrimination of two mixed qubit states for a measurement that allows a fixed rate of inconclusive results(FRIR). Our strategy for the problem is to transform the FRIR of two qubit states into a…

Quantum Physics · Physics 2017-10-17 Donghoon Ha , Younghun Kwon

Maximum likelihood quantum state tomography yields estimators that are consistent, provided that the likelihood model is correct, but the maximum likelihood estimators may have bias for any finite data set. The bias of an estimator is the…

Quantum Physics · Physics 2017-02-15 G. B. Silva , S. Glancy , H. M. Vasconcelos

Error probability is a popular and well-studied optimization criterion in discriminating non-orthogonal quantum states. It captures the threat from an adversary who can only query the actual state once. However, when the adversary is able…

Quantum Physics · Physics 2015-05-11 Weien Chen , Yongzhi Cao , Hanpin Wang , Yuan Feng

We consider the unambiguous discrimination of multipartite quantum states and provide an upper bound for the maximum success probability of optimal local discrimination. We also provide a necessary and sufficient condition to realize the…

Quantum Physics · Physics 2023-01-10 Donghoon Ha , Jeong San Kim

We relate the the distinguishability of quantum states with their robustness of the entanglement, where the robustness of any resource quantifies how tolerant it is to noise. In particular, we identify upper and lower bounds on the…

Quantum Physics · Physics 2025-12-24 Debarupa Saha , Kornikar Sen , Chirag Srivastava , Ujjwal Sen

We study the relationship between the entanglement, mixedness and energy of two-qubit and two-mode Gaussian quantum states. We parametrize the set of allowed states of these two fundamentally different physical systems using measures of…

Quantum Physics · Physics 2009-11-13 Derek McHugh , Mario Ziman , Vladimir Buzek

The state of a quantum system may be steered towards a predesignated target state, employing a sequence of weak $\textit{blind}$ measurements (where the detector's readouts are traced out). Here we analyze the steering of a two-level system…

Quantum Physics · Physics 2022-01-19 Parveen Kumar , Kyrylo Snizhko , Yuval Gefen , Bernd Rosenow

We consider the distinguishability of Gaussian states from the view point of continuous-variable quantum cryptography using post-selection. Specifically, we use the probability of error to distinguish between two pure coherent (squeezed)…

Quantum Physics · Physics 2015-05-13 Christian Weedbrook , Daniel J. Alton , Thomas Symul , Ping Koy Lam , Timothy C. Ralph

Extracting information from quantum devices has long been a crucial problem in the field of quantum mechanics. By performing elaborate measurements, quantum state tomography, an important and fundamental tool in quantum science and…

Quantum Physics · Physics 2022-06-24 Yu Wang , Keren Li

Experimental determination of an unknown quantum state usually requires several incompatible measurements. However, it is also possible to determine the full quantum state from a single, repeated measurement. For this purpose, the quantum…

Quantum Physics · Physics 2008-03-25 Xinhua Peng , Jiangfeng Du , Dieter Suter