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A generalized Bloch sphere, in which the states of a quantum entity of arbitrary dimension are geometrically represented, is investigated and further extended, to also incorporate the measurements. This extended representation constitutes a…

Quantum Physics · Physics 2015-12-16 Diederik Aerts , Massimiliano Sassoli de Bianchi

The inherent irreversibility of quantum dynamics for open systems poses a significant barrier to the inversion of unknown quantum processes. To tackle this challenge, we propose the framework of virtual combs that exploit the unknown…

Quantum Physics · Physics 2024-07-23 Chengkai Zhu , Yin Mo , Yu-Ao Chen , Xin Wang

We study chaos and scrambling in unitary channels by considering their entanglement properties as states. Using out-of-time-order correlation functions to diagnose chaos, we characterize the ability of a channel to process quantum…

High Energy Physics - Theory · Physics 2016-03-23 Pavan Hosur , Xiao-Liang Qi , Daniel A. Roberts , Beni Yoshida

Non-Markovianty of open quantum systems dynamics is a physically relevant property which is usually associated with the backflow of (quantum) information. Using this paradigmatic marker, we develop an operational framework to investigate…

Quantum Physics · Physics 2024-07-16 Thiago Melo D. Azevedo , Cristhiano Duarte , Nadja K. Bernardes

Quantum operations, or quantum channels cannot be inverted in general. An arbitrary state passing through a quantum channel looses its fidelity with the input. Given a quantum channel ${\cal E}$, we introduce the concept of its…

Quantum Physics · Physics 2020-03-25 Vahid Karimipour , Fabio Benatti , Roberto Floreanini

Quantum channels represent a broad spectrum of operations crucial to quantum information theory, encompassing everything from the transmission of quantum information to the manipulation of various resources. In the domain of states, the…

Quantum Physics · Physics 2025-05-15 Gilad Gour , Doyeong Kim , Takla Nateeboon , Guy Shemesh , Goni Yoeli

We consider the fundamental protocol of dense coding of classical information assuming that noise affects both the forward and backward communication lines between Alice and Bob. Assuming that this noise is described by the same quantum…

Quantum Physics · Physics 2020-04-13 Riccardo Laurenza , Cosmo Lupo , Seth Lloyd , Stefano Pirandola

The multichannel generalization of the theory of spectral, scattering and decay control is presented. New universal algorithms of construction of complex quantum systems with given properties are suggested. Particularly, transformations of…

Quantum Physics · Physics 2009-11-07 V. M. Chabanov , B. N. Zakhariev , I. V. Amirkhanov

Most coding theorems in quantum Shannon theory can be proven using the decoupling technique: to send data through a channel, one guarantees that the environment gets no information about it; Uhlmann's theorem then ensures that the receiver…

Quantum Physics · Physics 2014-07-16 Frédéric Dupuis , Oleg Szehr , Marco Tomamichel

Probabilistic error cancellation is an attempt to reverse the effect of dissipative noise channels on quantum computers by applying unphysical channels after the execution of a quantum algorithm on noisy hardware. We investigate on general…

The possibility of stochastic resonance of a quantum channel and hence the noise enhanced capacity of the channel is explored by considering the depolarizing channel. The fidelity of the channel is also considered. Although there is no…

Statistical Mechanics · Physics 2007-05-23 Julian Juhi-Lian Ting

If two identical copies of a completely depolarizing channel are put into a superposition of their possible causal orders, they can transmit non-zero classical information. Here, we study how well we can transmit classical information with…

Quantum Physics · Physics 2021-06-23 Sk Sazim , Michal Sedlak , Kratveer Singh , Arun Kumar Pati

A family of quantum cloning machines is introduced that produce two approximate copies from a single quantum bit, while the overall input-to-output operation for each copy is a Pauli channel. A no-cloning inequality is derived, describing…

Quantum Physics · Physics 2009-10-31 Nicolas J. Cerf

We consider entanglement-assisted communication over the qubit depolarizing channel under the security requirement of covert communication, where not only the information is kept secret, but the transmission itself must be concealed from…

Quantum Physics · Physics 2025-02-28 Elyakim Zlotnick , Boulat Bash , Uzi Pereg

We demonstrate how insights gained from reformulating the problem of quantum teleportation into one of reversing quantum operations, and designing optimum completely positive maps for teleportation, can enable one to explore optimal…

Quantum Physics · Physics 2007-05-23 Ye Yeo

In this work, we study two different approaches to defining the entropy of a quantum channel. One of these is based on the von Neumann entropy of the corresponding Choi-Jamio{\l}kowski state. The second one is based on the relative entropy…

Quantum Physics · Physics 2021-08-17 Dariusz Kurzyk , Łukasz Pawela , Zbigniew Puchała

Quantum simulation is of great importance in quantum information science. Here, we report an experimental quantum channel simulator imbued with an algorithm for imitating the behavior of a general class of quantum systems. The reported…

Problem of classification of parallel quantum channels for information transfer is studied by method of ladder operators. Detailed compared to http://arxiv.org/abs/quant-ph/0702076 presentation of method of ladder operators is given.…

Quantum Physics · Physics 2008-07-02 Constantin V. Usenko

The quantum-mechanical expression for the polarization of a crystalline solid does not bear any resemblance to the (trivial) expression for the dipole of a bounded crystallite; and in fact it has been proved via a conceptually different…

Materials Science · Physics 2021-02-08 Raffaele Resta

We study spin squeezing under non-Markovian channels, and consider an ensemble of $N$ independent spin-1/2 particles with exchange symmetry. Each spin interacts with its own bath, and the baths are independent and identical. For this kind…

Quantum Physics · Physics 2015-06-04 Xiaolei Yin , Jian Ma , Xiaoguang Wang , Franco Nori