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An upper limit is given to the amount of quantum information that can be transmitted reliably down a noisy, decoherent quantum channel. A class of quantum error-correcting codes is presented that allow the information transmitted to attain…

Quantum Physics · Physics 2009-10-30 Seth Lloyd

The classical product state capacity of a noisy quantum channel with memory is investigated. A forgetful noise-memory channel is constructed by Markov switching between two depolarizing channels which introduces non-Markovian noise…

Quantum Physics · Physics 2009-06-23 Jeroen Wouters , Ismail Akhalwaya , Mark Fannes , Francesco Petruccione

Quantum noise limits the use of quantum memory in high energy physics simulations. In particular, it breaks the gauge symmetry of stored quantum states. We examine this effect for abelian and nonabelian theories and demonstrate that…

High Energy Physics - Lattice · Physics 2023-01-25 Erik J. Gustafson , Henry Lamm

A generic qubit unitary operator affected by quantum noise is duplicated and inserted in a coherently superposed channel, superposing two paths offered to a probe qubit across the noisy unitary, and driven by a control qubit. A…

Quantum Physics · Physics 2021-10-14 Francois Chapeau-Blondeau

The optimal performance of a communication network is limited not only by the quality of point-to-point channels, but by the efficacy of its constituent technologies. Understanding the limits of quantum networks requires an understanding of…

Quantum Physics · Physics 2022-07-13 Cillian Harney , Stefano Pirandola

Absolutely maximally entangled states are quantum states that exhibit maximal entanglement across any bipartition, making them valuable for applications. This study investigates the behavior of qubit AME states under the influence of noisy…

Quantum Physics · Physics 2025-05-13 Maria Stawska , Jan Wójcik , Andrzej Grudka , Antoni Wójcik

We address the question of optimality of entangled input states in quantum Gaussian memory channels. For a class of such channels, that can be traced back to the memoryless setting, we state a criterion which relate the optimality of…

Quantum Physics · Physics 2010-05-18 C. Lupo , S. Mancini

Current advancements in communication equipment demand the investigation of classical information transfer over quantum channels, by encompassing realistic scenarios in finite dimensions. To address this issue, we develop a framework for…

Quantum Physics · Physics 2026-01-08 Sudipta Mondal , Pritam Halder , Saptarshi Roy , Aditi Sen De

We study the super dense coding capacity in the presence of quantum channels with correlated noise. We investigate both the cases of unitary and non-unitary encoding. Pauli channels for arbitrary dimensions are treated explicitly. The super…

Quantum Physics · Physics 2011-10-07 Zahra Shadman , Hermann Kampermann , Chiara Macchiavello , Dagmar Bruß

Determining whether a noisy quantum channel can be used to reliably transmit quantum information at a non-zero rate is a challenging problem in quantum information theory. This is because it requires computation of the channel's coherent…

Quantum Physics · Physics 2024-10-24 Satvik Singh , Nilanjana Datta

Quantum channel capacity is a fundamental quantity in order to understand how good can quantum information be transmitted or corrected when subjected to noise. However, it is generally not known how to compute such quantities, since the…

Quantum Physics · Physics 2023-09-20 Josu Etxezarreta Martinez , Antonio deMarti iOlius , Pedro M. Crespo

Noisy quantum channels may be used in many information carrying applications. We show that different applications may result in different channel capacities. Upper bounds on several of these capacities are proved. These bounds are based on…

Quantum Physics · Physics 2009-10-30 Howard Barnum , M. A. Nielsen , Benjamin Schumacher

Designing encoding and decoding circuits to reliably send messages over many uses of a noisy channel is a central problem in communication theory. When studying the optimal transmission rates achievable with asymptotically vanishing error…

Quantum Physics · Physics 2024-11-07 Matthias Christandl , Alexander Müller-Hermes

The non-increasing behavior of quantum coherence during any incoherent quantum process such as an incoherent quantum channel occurring in a noisy environment is a general property of quantum coherence. We address that the concatenation of…

Quantum Physics · Physics 2021-12-22 Durgun Duran

Optimization methods aimed at estimating the capacities of a general Gaussian channel are developed. Specifically evaluation of classical capacity as maximum of the Holevo information is pursued over all possible Gaussian encodings for the…

Quantum Physics · Physics 2012-09-12 Oleg V. Pilyavets , Cosmo Lupo , Stefano Mancini

We investigate all possible noise environments for controlled remote state preparation. We find that the optimal efficiency is not only dependent on the isolate decay rate but also dependent on the coupling term of environments. Such a…

Quantum Physics · Physics 2016-04-06 Yuan-hua Li , Zisheng Wang , Hua-qing Zhou , Xian-feng Chen

In this paper, we revisit the problem of finding the average capacity of the Gaussian feedback channel. First, we consider the problem of finding the average capacity of the analog Gaussian noise channel where the noise has an arbitrary…

Information Theory · Computer Science 2019-01-24 Ather Gattami

Quantum channels can be activated by a kind of channels whose quantum capacity is zero. This activation effect might be useful to overcome noise of channels by attaching other channels which can enhance the capacity of a given channel. In…

Quantum Physics · Physics 2018-07-26 Youngrong Lim , Soojoon Lee

Two new classes of quantum channels, which we call more capable and less noisy, are introduced. The more capable class consists of channels such that the quantum capacities of the complementary channels to the environments are zero. The…

Quantum Physics · Physics 2012-01-26 Shun Watanabe

Quantum states naturally decay under noise. Many earlier works have quantified and demonstrated lower bounds on the decay rate, showing exponential decay in a wide variety of contexts. Here we study the converse question: are there uniform…

Quantum Physics · Physics 2024-01-01 Nicholas Laracuente , Graeme Smith