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We investigate the coherence of quantum channels using the Choi-Jamio\l{}kowski isomorphism. The relation between the coherence and the purity of the channel respects a duality relation. It characterizes the allowed values of coherence when…

Quantum Physics · Physics 2018-09-14 Chandan Datta , Sk Sazim , Arun K. Pati , Pankaj Agrawal

A quantum control landscape is defined as the physical objective as a function of the control variables. In this paper the control landscapes for two-level open quantum systems, whose evolution is described by general completely positive…

Quantum Physics · Physics 2008-01-15 Alexander Pechen , Dmitrii Prokhorenko , Rebing Wu , Herschel Rabitz

The coexistence of quantum and classical signals over the same optical fiber with minimal degradation of the transmitted quantum information is critical for operating large-scale quantum networks over the existing communications…

We investigate the coherence of quantum channels and establish a resource theory for quantifying the coherence of quantum channels via Choi matrix. To this aim, we define the incoherent channels and incoherent superchannels. This theory…

Quantum Physics · Physics 2019-11-12 Jianwei Xu

This work derives an analytical formula for the asymptotic state---the quantum state resulting from an infinite number of applications of a general quantum channel on some initial state. For channels admitting multiple fixed or rotating…

Quantum Physics · Physics 2019-06-07 Victor V. Albert

We investigate the possibility of dividing quantum channels into concatenations of other channels, thereby studying the semigroup structure of the set of completely-positive trace-preserving maps. We show the existence of 'indivisible'…

Mathematical Physics · Physics 2015-06-26 Michael M. Wolf , J. Ignacio Cirac

Surprisingly often decoherence is due to classical fluctuations of ambient fields and may thus be described in terms of random unitary (RU) dynamics. However, there are decoherence channels where such a representation cannot exist. Based on…

Quantum Physics · Physics 2015-12-09 Julius Kayser , Kimmo Luoma , Walter T. Strunz

Quantum channels, also called quantum operations, are linear, trace preserving and completely positive transformations in the space of quantum states. Such operations describe discrete time evolution of an open quantum system interacting…

Quantum Physics · Physics 2011-10-04 Wojciech Roga

By using the Choi-Jamio{\l}kowski isomorphism, we propose a well-defined coherence measure of quantum channels based on the generalized $\alpha$-$z$-relative R\'{e}nyi entropy. In addition, we present an alternative coherence measure of…

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

Quantum channels describe subsystem or open system evolution. Using the classical Koopman operator that evolves functions on phase space, 4 classical Koopman channels are identified that are analogs of the 4 possible quantum channels in a…

Quantum Physics · Physics 2024-07-22 Bidhi Vijaywargia , Arul Lakshminarayan

The study of quantum channels is the fundamental field and promises wide range of applications, because any physical process can be represented as a quantum channel transforming an initial state into a final state. Inspired by the method…

Quantum Physics · Physics 2017-06-27 Shi-Jie Wei , Tao Xin , Gui-Lu Long

This paper introduces a method for calculating the quantum relative entropy of channels, an essential quantity in quantum channel discrimination and resource theories of quantum channels. By building on recent developments in the…

Quantum Physics · Physics 2026-04-16 Gereon Koßmann , Mark M. Wilde

A quantum holonomy reflects the curvature of some underlying structure of quantum mechanical systems, such as that associated with quantum states. Here, we extend the notion of holonomy to families of quantum channels, i.e., trace…

Quantum Physics · Physics 2016-03-28 David Kult , Johan Åberg , Erik Sjöqvist

Continuity properties of the output entropy of positive linear maps between Banach spaces of trace class operators are investigated with the special attention to the classes of quantum channels and operations. It is shown that finiteness of…

Quantum Physics · Physics 2011-10-04 M. E. Shirokov

A quantum channel will have a Choi representation from which the complete positivity (CP) can be determined in a number of different ways. Every method relies on Choi's proof which relates CP to the positive semi-definiteness of a specially…

Quantum Physics · Physics 2014-07-22 James M. McCracken

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

Quantum process tomography (QPT) plays a central role in characterizing quantum gates and circuits, diagnosing quantum devices, calibrating hardware, and supporting quantum error correction. However, conventional QPT methods face challenges…

Quantum Physics · Physics 2026-02-06 Huynh Le Dan Linh , Vu Tuan Hai , Le Bin Ho

Constructing all extreme instances of the set of completely positive trace-preserving (CPTP) maps, i.e., quantum channels, is a challenging valuable open problem in quantum information theory. Here we introduce a systematic approach that…

Quantum Physics · Physics 2022-10-10 Laleh Memarzadeh , Barry C. Sanders

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

We introduce three metrics on the set of quantum probability measures over a compact Hausdorff space and characterize them in terms of the completely bounded norm of the corresponding unital completely positive maps. We extend the existing…

Operator Algebras · Mathematics 2024-09-26 Georgios Baziotis