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Related papers: Strong* convergence of quantum channels

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Most general dynamics of an open quantum system is commonly represented by a quantum channel, which is a completely positive trace-preserving map (CPTP or Kraus map). Well-known are the representations of quantum channels by Choi matrices…

Quantum Physics · Physics 2025-06-10 Ivan Russkikh , Boris Volkov , Alexander Pechen

Coherence is a basic notion for quantum states. Instead of quantum states, in this work, We establish a resource theory for quantifying the coherence of Gaussian channels. To do this, we propose the definitions of incoherent Gaussian…

Quantum Physics · Physics 2019-08-15 Jianwei Xu

Unambiguous unitary maps and unambiguous unitary quantum channels are introduced and some of their properties are derived. These properties ensure certain simple form for the measurements involved in realizing an unambiguous unitary quantum…

Quantum Physics · Physics 2008-11-14 Shengjun Wu , Xuemei Chen

We introduce the concept of quasi-inverse of quantum and classical channels, prove general properties of these inverses and determine them for a large class of channels acting in an arbitrary finite dimension. Therefore we extend the…

Quantum Physics · Physics 2021-08-11 Fereshte Shahbeigi , Koorosh Sadri , Morteza Moradi , Karol Życzkowski , Vahid Karimipour

We consider the transmission of classical information through a degraded broadcast channel, whose outputs are two quantum systems, with the state of one being a degraded version of the other. Yard et al. proved that the capacity region of…

Quantum Physics · Physics 2019-05-03 Hao-Chung Cheng , Nilanjana Datta , Cambyse Rouzé

Distinguishability is fundamental to information theory and extends naturally to quantum systems. While quantum state discrimination is well understood, quantum channel discrimination remains challenging due to the dynamic nature of…

Quantum Physics · Physics 2025-07-15 Kun Fang , Gilad Gour , Xin Wang

In this paper we present a simple proof of the strong converse for identification via discrete memoryless quantum channels, based on a novel covering lemma. The new method is a generalization to quantum communication channels of Ahlswede's…

Quantum Physics · Physics 2007-05-23 R. Ahlswede , A. Winter

Quantum channels, pivotal in information processing, describe transformations within quantum systems and enable secure communication and error correction. Ergodic and mixing properties elucidate their behavior. In this paper, we establish a…

Quantum Physics · Physics 2024-07-24 Abdessatar Souissi , Abdessatar Barhoumi

Quantum information processing and computing tasks can be understood as quantum networks, comprising quantum states and channels and possible physical transformations on them. It is hence pertinent to estimate the change in informational…

Quantum Physics · Physics 2026-03-17 Sohail , Vivek Pandey , Uttam Singh , Siddhartha Das

Coherent superposition is a key feature of quantum mechanics that underlies the advantage of quantum technologies over their classical counterparts. Recently, coherence has been recast as a resource theory in an attempt to identify and…

By using the Choi-Jamio{\l}kowski isomorphism, we propose two classes of coherence monotones of quantum channels based on the unified $(r,s)$-relative entropy and the sandwiched R\'{e}nyi relative entropy. Elegant properties of the…

Quantum Physics · Physics 2025-06-13 Jiaorui Fan , Zhaoqi Wu , Shao-Ming Fei

Coherent electron transport through a quantum channel in the presence of a general extended scattering potential is investigated using a T-matrix Lippmann-Schwinger approach. The formalism is applied to a quantum wire with Gaussian type…

The set of Entanglement Saving (ES) quantum channels is introduced and characterized. These are completely positive, trace preserving transformations which when acting locally on a bipartite quantum system initially prepared into a…

Quantum Physics · Physics 2016-05-24 Ludovico Lami , Vittorio Giovannetti

The concept of stochastic resonance in nonlinear dynamics is applied to interpret the capacity of noisy quantum channels. The two-Pauli channel is used to illustrate the idea. The fidelity of the channel is also considered. Noise…

Quantum Physics · Physics 2008-12-18 Julian Juhi-Lian Ting

We establish the classical capacity of optical quantum channels as a sharp transition between two regimes---one which is an error-free regime for communication rates below the capacity, and the other in which the probability of correctly…

Quantum Physics · Physics 2015-03-17 Bhaskar Roy Bardhan , Raul Garcia-Patron , Mark M. Wilde , Andreas Winter

This paper studies the difficulty of discriminating between an arbitrary quantum channel and a "replacer" channel that discards its input and replaces it with a fixed state. We show that, in this particular setting, the most general…

Quantum Physics · Physics 2016-06-07 Tom Cooney , Milán Mosonyi , Mark M. Wilde

A unified approach to prove the converses for the quantum channel capacity theorems is presented. These converses include the strong converse theorems for classical or quantum information transfer with error exponents and novel explicit…

Quantum Physics · Physics 2013-03-14 Naresh Sharma , Naqueeb Ahmad Warsi

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

It is proved that every doubly stochastic quantum channel that is properly averaged with the completely depolarizing channel can be written as a convex combination of unitary channels. As a consequence, we find that the collection of…

Quantum Physics · Physics 2008-07-18 John Watrous

The quantum capacity of bosonic Gaussian quantum channels can be non-additive in a particularly striking way: a pair of such optical-fiber type channels can individually have zero quantum capacity but super-activate each other such that the…

Quantum Physics · Physics 2013-12-23 Daniel Lercher , Géza Giedke , Michael M. Wolf