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Related papers: Broadcasting Quantum Fisher Information

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We derive the optimal universal broadcasting for mixed states of qubits. We show that the nobroadcasting theorem cannot be generalized to more than a single input copy. Moreover, for four or more input copies it is even possible to purify…

Quantum Physics · Physics 2007-05-23 Giacomo Mauro D'Ariano , Chiara Macchiavello , Paolo Perinotti

We prove an extended convexity for quantum Fisher information of a mixed state with a given convex decomposition. This convexity introduces a bound which has two parts: i. classical part associated to the Fisher information of the…

Quantum Physics · Physics 2015-04-09 S. Alipour , A. T. Rezakhani

Quantum mechanics gives a new breakthrough to the field of parameter estimation. In the realm of quantum metrology, the precision of parameter estimation is limited by the quantum Fisher information. We introduce the measures of partial…

Quantum Physics · Physics 2024-11-14 Dong-Ping Xuan , Zhong-Xi Shen , Wen Zhou , Hua Nan , Shao-Ming Fei , Zhi-Xi Wang

Quantum Fisher information (QFI) sets the ultimate precision of optical phase measurements and reveals multiphoton entanglement, but it is not accessible with conventional photodetection. We theoretically predict that a photodetector…

Mesoscale and Nanoscale Physics · Physics 2026-04-01 Evgenii Barts , Takahiro Morimoto , Naoto Nagaosa

Masking of quantum information spreads it over nonlocal correlations and hides it from the subsystems. It is known that no operation can simultaneously mask all pure states [Phys. Rev. Lett. 120, 230501 (2018)], so in what sense is quantum…

In estimating an unknown parameter of a quantum state the quantum Fisher information (QFI) is a pivotal quantity, which depends on the state and its derivate with respect to the unknown parameter. We prove the continuity property for the…

Quantum Physics · Physics 2019-09-16 A. T. Rezakhani , M. Hassani , S. Alipour

Distributed quantum information processing seeks to overcome the scalability limitations of monolithic quantum devices by interconnecting multiple quantum processing nodes via classical and quantum communication. This approach extends the…

Quantum Physics · Physics 2025-10-20 Johannes Knörzer , Xiaoyu Liu , Benjamin F. Schiffer , Jordi Tura

Recent years have seen significant activity on the problem of using data for the purpose of learning properties of quantum systems or of processing classical or quantum data via quantum computing. As in classical learning, quantum learning…

Quantum Physics · Physics 2024-04-17 Leonardo Banchi , Jason Luke Pereira , Sharu Theresa Jose , Osvaldo Simeone

An expression is derived characterizing the set of admissible rate pairs for simultaneous transmission of classical and quantum information over a given quantum channel, generalizing both the classical and quantum capacities of the channel.…

Quantum Physics · Physics 2007-05-23 I. Devetak , P. W. Shor

We raise the question whether there is a way to characterize the quantum information transport properties of a medium or material. For this analysis the special features of quantum information have to be taken into account. We find that…

Quantum Physics · Physics 2013-03-22 Johan Aberg , Stefan Hengl , Renato Renner

Quantum information cannot be broadcast -- an intrinsic limitation imposed by quantum mechanics. However, recent advances in virtual operations offer new insights into the no-broadcasting theorem. Here, we focus on the practical utility and…

Quantum Physics · Physics 2025-09-30 Yunlong Xiao , Xiangjing Liu , Zhenhuan Liu

The importance of the quantum Fisher information metric is testified by the number of applications that this has in very different fields, ranging from hypothesis testing to metrology, passing through thermodynamics. Still, from the rich…

Quantum Physics · Physics 2024-04-30 Matteo Scandi , Paolo Abiuso , Jacopo Surace , Dario De Santis

I show that the cloneability of information is the key difference between classical computer and quantum computer. As information stored and processed by neurons is cloneable, brain (human or non-human) is a classical computer. Penrose…

General Physics · Physics 2022-04-12 Biao Wu

We discuss how quantum information distribution can improve the performance of some quantum computation tasks. This distribution can be naturally implemented with different types of quantum cloning procedures. We give two examples of tasks…

Quantum Physics · Physics 2007-05-23 Ernesto F. Galvao , Lucien Hardy

Although information, strictly speaking, is not a physical entity, it generally requires physical entities as its carriers, e.g., writing it down on paper, encoding it with quantum particles, or transmitting it using electro-magnetic…

Quantum Physics · Physics 2026-04-21 Guang Ping He

Quantum networks connect systems at separate locations via quantum links, enabling a wide range of quantum information tasks between distant parties. Large-scale networks have the potential to enable global secure communication, distributed…

Quantum information theory is the study of the achievable limits of information processing within quantum mechanics. Many different types of information can be accommodated within quantum mechanics, including classical information, coherent…

Quantum Physics · Physics 2007-05-23 M. A. Nielsen

One of the most intriguing facts about communication using quantum states is that these states cannot be used to transmit more classical bits than the number of qubits used, yet there are ways of conveying information with exponentially…

Quantum Physics · Physics 2007-05-23 Ashwin Nayak , Amnon Ta-Shma , David Zuckerman

In recent proposals for achieving optical super-resolution, variants of the Quantum Fisher Information (QFI) quantify the attainable precision. We find that claims about a strong enhancement of the resolution resulting from coherence…

Quantum Physics · Physics 2019-11-14 Zdeněk Hradil , Jaroslav Řeháček , Luis Sánchez-Soto , Berthold-Georg Englert

We present here a scheme that relates seemingly two different kinds of physical impossibilities of quantum information processing. We derive, exact flipping of three arbitrary states not lying in one great circle is not possible with…

Quantum Physics · Physics 2009-11-11 Indrani Chattopadhyay , Debasis Sarkar