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Compound channel models offer a simple and straightforward way of analyzing the stability of decoder design under model variations. With this work we provide a coding theorem for a large class of practically relevant compound channel…

Information Theory · Computer Science 2021-05-11 Andrea Cacioppo , Janis Nötzel , Matteo Rosati

The emerging quantum technologies rely on our ability to establish and control quantum systems in nonclassical states, exhibiting entanglement and quantum coherence. It is thus crucial to understand how entanglement and coherence can be…

Quantum Physics · Physics 2022-06-22 Masaya Takahashi , Swapan Rana , Alexander Streltsov

A class of lower bounds for the entanglement cost of any quantum state was recently introduced in [arXiv:2111.02438] in the form of entanglement monotones known as the tempered robustness and tempered negativity. Here we extend their…

Quantum Physics · Physics 2023-02-16 Ludovico Lami , Bartosz Regula

We present two projects concerning the main part of my PhD work. In the first one we study quantum channels, which are the most general operations mapping quantum states into quantum states, from the point of view of their divisibility…

Quantum Physics · Physics 2020-09-02 David Davalos

Quantum Gaussian channels play a key role in quantum information theory. In particular, the attenuation and amplification channels are useful to describe noise and decoherence effects on continuous variables systems. They are directly…

Quantum Physics · Physics 2021-03-22 Jonas F. G. Santos , C. H. S. Vieira

Quantum error correction (QEC) is an essential concept for any quantum information processing device. Typically, QEC is designed with minimal assumptions about the noise process; this generic assumption exacts a high cost in efficiency and…

Quantum Physics · Physics 2007-06-26 Andrew S. Fletcher

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

We introduce potential capacities of quantum channels in an operational way and provide upper bounds for these quantities, which quantify the ultimate limit of usefulness of a channel for a given task in the best possible context.…

Quantum Physics · Physics 2016-02-17 Andreas Winter , Dong Yang

A controlled quantum dense coding scheme is investigated with a four-particle non-maximal quantum channel. The amount of classical information is shown to be capable of being controlled by the controllers through adjustments of the local…

Quantum Physics · Physics 2007-05-23 Chang-Bao Fu , Yan Xia , Bo-Xue Liu , Shou Zhang , Kyu-Hwang Yeon , Chung-In Um

We define the direct and reverse secret-key capacities of a memoryless quantum channel as the optimal rates that entanglement-based quantum key distribution protocols can reach by using a single forward classical communication (direct…

Quantum Physics · Physics 2009-02-09 Stefano Pirandola , Raul Garcia-Patron , Samuel L. Braunstein , Seth Lloyd

Quantum channels, a subset of quantum maps, describe the unitary and non-unitary evolution of quantum systems. We study a generalization of the concept of Pauli maps to the case of multipartite high dimensional quantum systems through the…

Quantum Physics · Physics 2024-04-25 Tomas Basile , Jose Alfredo de Leon , Alejandro Fonseca , Francois Leyvraz , Carlos Pineda

Recently, the projective robustness of quantum states has been introduced in [arXiv:2109.04481(2021)]. It shows that the projective robustness is a useful resource monotone and can comprehensively characterize capabilities and limitations…

Quantum Physics · Physics 2022-06-15 Mingfei Ye , Yu Luo , Zhihui Li , Yongming Li

Quantum channels underlie the dynamics of quantum systems, but in many practical settings it is the channels themselves that require processing. We establish universal limitations on the processing of both quantum states and channels,…

Quantum Physics · Physics 2021-07-21 Bartosz Regula , Ryuji Takagi

We analyze the quantum capacity of a unital quantum channel, using ideas from the proof of near-optimality of Petz recovery map [Barnum and Knill 2000] and give an upper bound on the quantum capacity in terms of regularized output $2$-norm…

Quantum Physics · Physics 2018-03-07 Anurag Anshu

We re-examine a non-Gaussian quantum error correction code designed to protect optical coherent-state qubits against errors due to an amplitude damping channel. We improve on a previous result [Phys. Rev. A 81, 062344 (2010)] by providing a…

Quantum Physics · Physics 2014-05-14 Ricardo Wickert , Peter van Loock

The quantum channel decomposition techniques, which contain the so-called probabilistic error cancellation and gate/wire cutting, are powerful approach for simulating a hard-to-implement (or an ideal) unitary operation by concurrently…

Quantum Physics · Physics 2023-08-30 Ryo Nagai , Shu Kanno , Yuki Sato , Naoki Yamamoto

This paper explores the computational complexity involved in determining the capacity of the band-limited additive colored Gaussian noise (ACGN) channel and its capacity-achieving power spectral density (p.s.d.). The study reveals that when…

Information Theory · Computer Science 2023-10-11 Holger Boche , Andrea Grigorescu , Rafael F. Schaefer , H. Vincent Poor

One of the major achievements of the recently emerged quantum information theory is the introduction and thorough investigation of the notion of quantum channel which is a basic building block of any data-transmitting or data-processing…

Quantum Physics · Physics 2012-03-23 A. S. Holevo , V. Giovannetti

We give necessary and sufficient conditions for a Gaussian quantum channel to have a dilation involving a passive, i.e., number-preserving unitary. We then establish a normal form of such channels: any passively dilatable channel is the…

Quantum Physics · Physics 2017-04-27 Martin Idel , Robert Koenig

Quantum Internet relies on quantum entanglement as a fundamental resource for secure and efficient quantum communication, reshaping data transmission. In this context, entanglement distillation emerges as a crucial process that plays a…

Quantum Physics · Physics 2024-07-30 Chengkai Zhu , Chenghong Zhu , Xin Wang