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Protocols for discriminating between a pair of channels or for estimating a channel parameter can often be aided by adaptivity or by entanglement between the probe states. This can make it difficult to bound the best possible performance…

Quantum Physics · Physics 2021-10-07 Jason L. Pereira , Leonardo Banchi , Stefano Pirandola

By utilizing single particle interferometry, the fidelity or coherence of a pair of quantum states is identified with their capacity for interference. We consider processes acting on the internal degree of freedom (e.g., spin or…

Quantum Physics · Physics 2009-11-13 Daniel K. L. Oi , Johan Aberg

A collection of quantum channels is called incompatible if they cannot be obtained as marginals from a single channel. No-cloning theorem is the most prominent instance of incompatibility of quantum channels. We show that every collection…

Quantum Physics · Physics 2020-03-24 Junki Mori

Quantum complexity measures the difficulty of obtaining a given state starting from a typically unentangled state. In this work, we show that complexity, when defined through the minimization of a Riemannian cost functional over the…

Quantum Physics · Physics 2025-06-05 Nadir Samos Sáenz de Buruaga

We derive a general limit on the fidelity of a quantum channel conveying an ensemble of pure states. Unlike previous results, this limit applies to arbitrary coding and decoding schemes, including nonunitary decoding. This establishes the…

Quantum Physics · Physics 2016-09-08 Howard Barnum , Christopher A. Fuchs , Richard Jozsa , Benjamin Schumacher

Recently quantum states discrimination has been frequently studied. In this paper we study them from the other way round, the likeness of two quantum states. The fidelity is used to describe the likeness of two quantum states. Then we…

Quantum Physics · Physics 2009-11-07 Fei Xue , Jiangfeng Du , Xianyi Zhou , Rongdian Han , Jihui Wu

We investigate quantum teleportation through noisy quantum channels by solving analytically and numerically a master equation in the Lindblad form. We calculate the fidelity as a function of decoherence rates and angles of a state to be…

Quantum Physics · Physics 2009-11-07 Sangchul Oh , Soonchil Lee , Hai-woong Lee

We consider quantum teleportation when the given entanglement channel is an arbitrary multiparticle state. A general criterion is presented, which allows one to judge if the channel can be used to teleport faithfully an arbitrary quantum…

Quantum Physics · Physics 2015-05-13 Chi-Yee Cheung , Zhan-Jun Zhang

We provide a complete set of game-theoretic conditions equivalent to the existence of a transformation from one quantum channel into another one, by means of classically correlated pre/post processing maps only. Such conditions naturally…

Quantum Physics · Physics 2018-05-16 Denis Rosset , Francesco Buscemi , Yeong-Cherng Liang

We show a simple and systematic way to certify any given bipartite state as the unique joint $1$-eigenstate of two separable projectors, each of which can be measured with simple local observables. This is practically useful, as the…

Quantum Physics · Physics 2025-12-18 Jennifer Ahiable , Andreas Winter

We analyze different aspects of multiparty communication over quantum memoryless channels and generalize some of key results known from bipartite channels to that of multiparty scenario. In particular, we introduce multiparty versions of…

Quantum Physics · Physics 2009-11-13 Maciej Demianowicz , Pawel Horodecki

By relevant modifications, the known global-fidelity limits of state-dependent cloning are extended to mixed quantum states. We assume that the ancilla contains some a priori information about the input state. As it is shown, the obtained…

Quantum Physics · Physics 2009-11-10 Alexey E. Rastegin

The fidelity susceptibility measures sensitivity of eigenstates to a change of an external parameter. It has been fruitfully used to pin down quantum phase transitions when applied to ground states (with extensions to thermal states). Here…

Disordered Systems and Neural Networks · Physics 2020-04-10 Piotr Sierant , Artur Maksymov , Marek Kuś , Jakub Zakrzewski

A protocol for transferring an unknown single qubit state has quantum features when the average fidelity of the outcomes is greater than 2/3. We use the probabilistic and unambiguous state extraction scheme as a mechanism to redistribute…

Quantum Physics · Physics 2016-06-22 Luis Roa , Robinson Gómez , Ariana Muñoz , Gautam Rai

We derive a relationship between two different notions of fidelity (entanglement fidelity and average fidelity) for a completely depolarizing quantum channel. This relationship gives rise to a quantum analog of the MacWilliams identities in…

Quantum Physics · Physics 2007-05-23 Peter Shor , Raymond Laflamme

Fidelity is a fundamental measure for the closeness of two quantum states, which is important both from a theoretical and a practical point of view. Yet, in general, it is difficult to give good estimates of fidelity, especially when one…

Quantum Physics · Physics 2022-03-31 András Gilyén , Alexander Poremba

We relate gate fidelities of experimentally realized quantum operations to the broadcasting property of their ideal operations, and show that the more parties a given quantum operation can broadcast to, the higher gate fidelities of its…

Quantum Physics · Physics 2011-06-30 Hyang-Tag Lim , Young-Sik Ra , Yong-Su Kim , Yoon-Ho Kim , Joonwoo Bae

Coherence and correlation are key features of the quantum system. Quantifying these quantities are astounding task in the framework of resource theory of quantum information processing. In this article, we identify an affinity-based metric…

Quantum Physics · Physics 2021-02-11 R. Muthuganesan , V. K. Chandrasekar , R. Sankaranarayanan

A two-dimensional quantum system with anyonic excitations can be considered as a quantum computer. Unitary transformations can be performed by moving the excitations around each other. Measurements can be performed by joining excitations in…

Quantum Physics · Physics 2009-10-30 A. Yu. Kitaev

Estimation of quantum states and measurements is crucial for the implementation of quantum information protocols. The standard method for each is quantum tomography. However, quantum tomography suffers from systematic errors caused by…

Quantum Physics · Physics 2018-10-19 Adam C. Keith , Charles H. Baldwin , Scott Glancy , E. Knill
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