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We study the problem of remote one-qubit mixed state creation using a pure initial state of two-qubit sender and spin-1/2 chain as a connecting line. We express the parameters of creatable states in terms of transition amplitudes. We show…

Quantum Physics · Physics 2015-07-30 G. A. Bochkin , A. I. Zenchuk

This paper provides a characterization for the set of antidegradable qubit channels. The characterization arises from the correspondence between the antidegradability of a channel and the symmetric extendibility of its Choi operator. Using…

Quantum Physics · Physics 2017-12-12 Connor Paddock , Jianxin Chen

We consider the general problem of the optimal transformation of N uses of (possibly different) unitary channels to a single use of another unitary channel in any finite dimension. We show how the optimal transformation can be fully…

Quantum Physics · Physics 2014-09-09 Alessandro Bisio , Giacomo Mauro D'Ariano , Paolo Perinotti , Michal Sedlak

In this paper, we propose an explicit scheme to fully recover a multiple-qubit state subject to a phase damping noise. We establish the theoretical framework and the operational procedure to restore an unknown initial quantum state for an…

Quantum Physics · Physics 2013-09-03 Xinyu Zhao , Samuel R. Hedemann , Ting Yu

The dynamics of quantum systems are generally described by a family of quantum channels (linear, completely positive and trace preserving maps). In this note, we mainly study the range of all possible values of…

Quantum Physics · Physics 2026-01-19 Yuan Li , Zhengli Chen , Zhihua Guo , Yongfeng Pang

We investigate the problem of optimally reversing the action of an arbitrary quantum channel C which acts independently on each component of an ensemble of n identically prepared d-dimensional quantum systems. In the limit of large…

Quantum Physics · Physics 2012-12-06 Peter Bowles , Madalin Guta , Gerardo Adesso

We propose a protocol to improve the accuracy of direct complex state measurements (DSM) by using rebits in real Hilbert spaces. We show that to improve the accuracy, the initial complex state should be decomposed into the real and…

Quantum Physics · Physics 2018-11-13 Le Bin Ho

In quantum-state tomography on sources with quantum degrees of freedom of large Hilbert spaces, inference of quantum states of light for instance, a complete characterization of the quantum states for these sources is often not feasible…

Quantum Physics · Physics 2013-11-14 Yong Siah Teo , Jaroslav Rehacek , Zdenek Hradil

Sampling is classically performed by recording the amplitude of an input signal at given time instants; however, sampling and reconstructing a signal using multiple devices in parallel becomes a more difficult problem to solve when the…

Signal Processing · Electrical Eng. & Systems 2020-04-22 Karen Adam , Adam Scholefield , Martin Vetterli

We present the optimal scheme for estimating a pure qubit state by means of local measurements on N identical copies. We give explicit examples for low N. For large N, we show that the fidelity saturates the collective measurement bound up…

Quantum Physics · Physics 2009-11-07 E. Bagan , M. Baig , R. Munoz-Tapia

Gaussian channels are the typical way to model the decoherence introduced by the environment in continuous-variable quantum states. It is known that those channels can be simulated by a teleportation protocol using as a resource state…

Quantum Physics · Physics 2018-12-05 Spyros Tserkis , Josephine Dias , Timothy C. Ralph

Quantum state tomography (QST) is the process of reconstructing the complete state of a quantum system (mathematically described as a density matrix) through a series of different measurements. These measurements are performed on a number…

Quantum Physics · Physics 2025-01-08 Hailan Ma , Zhenhong Sun , Daoyi Dong , Dong Gong

We examine stochastic maps in the context of quantum optics. Making use of the master equation, the damping basis, and the Bloch picture we calculate a non-unital, completely positive, trace-preserving map with unequal damping eigenvalues.…

Quantum Physics · Physics 2009-11-07 Sonja Daffer , Krzysztof Wodkiewicz , John K. McIver

This paper presents QCommE2E as an open-source simulation framework for end-to-end quantum communication systems, with explicit tutorial emphasis. The primary objective is to develop a comprehensive framework that includes transmitters,…

Quantum Physics · Physics 2026-05-26 Omar Alnaseri

We develop methods to efficiently reconstruct the topology and line parameters of a power grid from the measurement of nodal variables. We propose two compressed sensing algorithms that minimize the amount of necessary measurement resources…

Systems and Control · Computer Science 2019-07-10 Farnaz Basiri , Jose Casadiego , Marc Timme , Dirk Witthaut

This paper presents strategies for enhancing the robustness of bidirectional quantum teleportation (BQT) through environment-assisted and weak measurement techniques. BQT is a crucial component of distributed quantum networks, allowing for…

Quantum Physics · Physics 2025-08-01 Javid Ahmad Malik , Muzaffar Qadir Lone , Prince A Ganai

Quantum state tomography (QST) is essential for validating quantum devices but suffers from exponential scaling in system size. Neural-network quantum states, such as Restricted Boltzmann Machines (RBMs), can efficiently parameterize…

Quantum Physics · Physics 2026-01-30 Simon Tonner , Viet T. Tran , Richard Kueng

Purification of mixed states in Quantum Mechanics, by which we mean the transformation into pure states, has been viewed as an {\it Operation} in the sense of Kraus et al and explicit {\it Kraus Operators} \cite{kra1,kra2,kra3} have been…

Quantum Physics · Physics 2007-05-23 Chirag Dhara , N. D. Hari Dass

We address the fundamental task of converting $n$ uses of an unknown unitary transformation into a quantum state (i.e., storage) and later retrieval of the transformation. Specifically, we consider the case where the unknown unitary is…

We propose a method for partial state reconstruction of multiphoton states in multimode ($N$-photon $M$-mode) linear optical networks (LONs) employing only two bucket photon-number-resolving (PNR) detectors. The reconstructed…

Quantum Physics · Physics 2025-02-11 Tudor-Alexandru Isdrailǎ , Jun-Yi Wu
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