English
Related papers

Related papers: On Concurrence and Entanglement of Rank Two Channe…

200 papers

Entanglement is one of the fundamental properties of a quantum state and is a crucial differentiator between classical and quantum computation. There are many ways to define entanglement and its measure, depending on the problem or…

Quantum Physics · Physics 2025-01-07 Andrii Semenov , Niall Murphy , Simone Patscheider , Alessandra Bernardi , Elena Blokhina

We show that entanglement is a useful resource to enhance the mutual information of the depolarizing channel when the noise on consecutive uses of the channel has some partial correlations. We obtain a threshold in the degree of memory,…

Quantum Physics · Physics 2009-11-07 Chiara Macchiavello , G. Massimo Palma

We show that every entangled state provides an advantage in bi- and multi-channel discrimination that singles out its degree of entanglement, quantified in terms of its Schmidt number and of the corresponding robustness measures.

Quantum Physics · Physics 2019-04-17 Joonwoo Bae , Dariusz Chruściński , Marco Piani

In this paper we give a general integral representation for separable states in the tensor product of infinite dimensional Hilbert spaces and provide the first example of separable states that are not countably decomposable. We also prove…

Quantum Physics · Physics 2011-11-09 A. S. Holevo , M. E. Shirokov , R. F. Werner

The entanglement content of superpositions of quantum states is investigated based on a measure called {\it concurrence}. Given a bipartite pure state in arbitrary dimension written as the quantum superposition of two other such states, we…

Quantum Physics · Physics 2009-11-13 J. Niset , N. J. Cerf

Entanglement shared between the two ends of a quantum communication channel has been shown to be a useful resource in increasing both the quantum and classical capacities for these channels. The entanglement-assisted capacities were derived…

Quantum Physics · Physics 2009-11-07 Garry Bowen

Entanglement serves as a fundamental resource for various quantum information processing tasks. Fidelity of entanglement (which measures the proximity to a maximally entangled state) and various quantum entropies are key indicators for…

Quantum Physics · Physics 2025-10-21 Komal Kumar , Bivas Mallick , Tapaswini Patro , Nirman Ganguly

We present a method to detect properties of quantum channels, assuming that some a priori information about the form of the channel is available. The method is based on a correspondence with entanglement detection methods for multipartite…

Quantum Physics · Physics 2013-11-13 C. Macchiavello , M. Rossi

An active area of investigation in the search for quantum advantage is Quantum Machine Learning. Quantum Machine Learning, and Parameterized Quantum Circuits in a hybrid quantum-classical setup in particular, could bring advancements in…

Quantum Physics · Physics 2020-09-01 Thomas Hubregtsen , Josef Pichlmeier , Patrick Stecher , Koen Bertels

Nonlocality and entanglement are not only the fundamental characteristics of quantum mechanics but also important resources for quantum information and computation applications. Exploiting the quantitative relationship between the two…

Quantum Physics · Physics 2020-04-20 Zhaofeng Su , Haisheng Tan , Xiangyang Li

We investigate the problem of determining the parameters that describe a quantum channel. It is assumed that the users of the channel have at best only partial knowledge of it and make use of a finite amount of resources to estimate it. We…

We study the signatures of disorder in the production of orbital electron entanglement in quantum wires. Disordered entanglers suffer the effects of localization of the electron wave function and random fluctuations in the entanglement…

Mesoscale and Nanoscale Physics · Physics 2014-03-07 Alberto Aleta , Héctor Villarubia-Rojo , Diego Frustaglia , Víctor A. Gopar

We provide a class of positive and trace-preserving maps based on symmetric measurements. From these positive maps we present separability criteria, entanglement witnesses, as well as the lower bounds of concurrence. We show by detailed…

Quantum Physics · Physics 2024-05-21 Jiaxin Li , Hongmei Yao , Shao-Ming Fei , Zhaobing Fan , Haitao Ma

Nonlinear inequalities based on the quadratic Renyi entropy for mixed two-qubit states are characterized on the Entropy-Concurrence plane. This class of inequalities is stronger than Clauser-Horne-Shimony-Holt (CHSH) inequalities and, in…

Quantum Physics · Physics 2009-11-13 Fabio A. Bovino

We explore complementarity between output and environment of a quantum channel (or, more generally, CP map), making an observation that the output purity characteristics for complementary CP maps coincide. Hence, validity of the…

Quantum Physics · Physics 2007-07-05 A. S. Holevo

Entanglement is an important concept in quantum information, quantum communication, and quantum computing. We provide a geometrical analysis of entanglement and separability for all the rank-2 quantum mixed states: complete analysis for the…

Quantum Physics · Physics 2017-03-09 Michel Boyer , Rotem Liss , Tal Mor

We present some of the peculiar dynamics of two simple sans-entanglement quantum communication channels in a digestible form. Specifically, we contrast the classical gaussian additive channel to its quantum analogue and find that the…

Quantum Physics · Physics 2024-06-18 Miles Miller-Dickson , Christopher Rose

One of the most challenging open problems in quantum information theory is to clarify and quantify how entanglement behaves when part of an entangled state is sent through a quantum channel. Of central importance in the description of a…

Quantum Physics · Physics 2007-05-23 Frank Verstraete , Henri Verschelde

In this paper we solve the problem of analytic classification of plane curves singularities with two branches by presenting their normal forms. This is accomplished by means of a new analytic invariant that relates vectors in the tangent…

Algebraic Geometry · Mathematics 2016-01-28 Abramo Hefez , Marcelo Escudeiro Hernandes , Maria Elenice Rodrigues Hernandes

In this paper we use the method of a recent paper (quant-ph/0509101) to compute complementary channels for certain important cases, such as depolarizing and transpose-depolarizing channels. This method allows us to easily obtain the minimal…

Quantum Physics · Physics 2007-05-23 Nilanjana Datta , Alexander S. Holevo