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We consider quantum-information division, which is characterized by a channel whose outputs have no correlation and are not completely randomized. We show that the quantum-information division is possible in a probabilistic manner by…

Quantum Physics · Physics 2014-04-02 Yuji Sekino , Satoshi Ishizaka

We consider the task of distinguishing whether a quantum system is prepared in a state from one of several sets of quantum states. Assuming their convexity and stability under tensor product, we prove that the optimal error exponent for…

Quantum Physics · Physics 2025-11-18 Kun Fang , Masahito Hayashi

While the no-cloning theorem, which forbids the perfect copying of quantum states, is well-known as one of the defining features of quantum mechanics, the question of how well the theory allows a state to be cloned is yet to be completely…

Quantum Physics · Physics 2013-09-25 Alastair Kay , Ravishankar Ramanathan , Dagomir Kaszlikowski

Identifying the precise moment when a quantum channel undergoes a change is a fundamental problem in quantum information theory. We study how accurately one can determine the time at which a channel transitions to another. We investigate…

Quantum Physics · Physics 2026-04-15 Kenji Nakahira

The impossibility of simultaneously cloning non-orthogonal states lies at the foundations of quantum theory. Even when allowing for approximation errors, cloning an arbitrary unknown pure state requires as many initial copies as needed to…

Quantum Physics · Physics 2026-04-17 Nikhil Bansal , Matthias C. Caro , Gaurav Mahajan

A generalized universal quantum cloning machine is proposed which allows the input to be arbitrary states in symmetric subspace. And it reduces to the universal quantum cloning machine (UQCM) if the input are identical pure states. The…

Quantum Physics · Physics 2007-05-23 Heng Fan , Keiji Matsumoto , Xiang-Bin Wang , Hiroshi Imai , Miki Wadati

We study the procedure for sequential unambiguous state discrimination. A qubit is prepared in one of two possible states, and measured by two observers Bob and Charlie sequentially. A necessary condition for the state to be unambiguously…

Quantum Physics · Physics 2013-12-02 Chao-Qian Pang , Fu-Lin Zhang , Li-Fang Xu , Mai-Lin Liang , Jing-Ling Chen

For distinguishing quantum states sampled from a fixed ensemble, the gap in bipartite and single-party distinguishability can be interpreted as a nonlocality of the ensemble. In this paper, we consider bipartite state discrimination in a…

Quantum Physics · Physics 2018-09-18 Seiseki Akibue , Go Kato

Roa et al. showed that quantum state discrimination between two nonorthogonal quantum states does not require quantum entanglement but quantum dissonance only. We find that quantum coherence can also be utilized for unambiguous quantum…

Quantum Physics · Physics 2021-08-10 Sunho Kim , Longsuo Li , Asutosh Kumar , Chunhe Xiong , Sreetama Das , Ujjwal Sen , Arun Kumar Pati , Junde Wu

We give a lower bound on the probability of error in quantum state discrimination. The bound is a weighted sum of the pairwise fidelities of the states to be distinguished.

Quantum Physics · Physics 2016-11-15 Ashley Montanaro

Two pure orthogonal quantum states can be perfectly distinguished by sequential local action of multiple pairs of parties. However, this process typically leads to the complete dissolution of entanglement in the states being discriminated.…

Quantum Physics · Physics 2025-06-10 Debarupa Saha , Priya Ghosh , Kornikar Sen , Chirag Srivastava , Ujjwal Sen

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 propose a scheme of 1$\to$2 optimal universal asymmetric quantum telecloning of pure multiqubit states. In particular, we first investigate the asymmetric telecloning of arbitrary 2-qubit states and then extend it to the case of…

Quantum Physics · Physics 2007-05-23 Lin Chen , Yi-Xin Chen

We present the conditions under which probabilistic error-free discrimination of mixed states is possible, and provide upper and lower bounds on the maximum probability of success for the case of two mixed states. We solve certain special…

Quantum Physics · Physics 2007-05-23 Terry Rudolph , Robert W. Spekkens , Peter Shipley Turner

Attempts at cloning a quantum system result in the introduction of imperfections in the state of the copies. This is a consequence of the no-cloning theorem, which is a fundamental law of quantum physics and the backbone of security for…

Quantum Physics · Physics 2016-08-17 Frédéric Bouchard , Robert Fickler , Robert W Boyd , Ebrahim Karimi

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

Quantum state discrimination underlies various applications in quantum information processing tasks. It essentially describes the distinguishability of quantum systems in different states, and the general process of extracting classical…

Quantum Physics · Physics 2017-07-12 Joonwoo Bae , Leong-Chuan Kwek

We study the discrimination of N mixed quantum states in an optimal measurement that maximizes the probability of correct results while the probability of inconclusive results is fixed at a given value. After considering the discrimination…

Quantum Physics · Physics 2015-06-11 Ulrike Herzog

Quantum indistinguishability of non-orthogonal quantum states is a valuable resource in quantum information applications such as cryptography and randomness generation. In this article, we present a sequential state-discrimination scheme…

Quantum Physics · Physics 2026-04-28 Lemieux Wang , Hanwool Lee , Joonwoo Bae , Kieran Flatt

A method to compute the optimal success probability of discrimination of N arbitrary quantum states is presented, based on the decomposition of any N-outcome measurement into sequences of nested two-outcome ones. In this way the…

Quantum Physics · Physics 2017-04-12 Matteo Rosati , Giacomo De Palma , Andrea Mari , Vittorio Giovannetti