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A quantum trajectory describes the evolution of a quantum system undergoing indirect measurement. In the discrete-time setting, the state of the system is updated by applying Kraus operators according to the measurement results. From an…

Quantum Physics · Physics 2022-04-04 Maël Bompais , Nina H. Amini , Clément Pellegrini

Quantum process tomography, the standard procedure to characterize any quantum channel in nature, is affected by a circular argument: in order to characterize the channel, the tomographic preparation and measurement need in turn to be…

Quantum Physics · Physics 2016-06-13 Michele Dall'Arno , Sarah Brandsen , Francesco Buscemi

Spectral properties of an arbitrary matrix can be characterized by the entropy of its rescaled singular values. Any quantum operation can be described by the associated dynamical matrix or by the corresponding superoperator. The entropy of…

Quantum Physics · Physics 2013-05-27 Wojciech Roga , Zbigniew Puchała , Łukasz Rudnicki , Karol Życzkowski

Matrix representations of quantum operators are computationally complete but often obscure the structural topology of information flow within a quantum circuit \cite{nielsen2000}. In this paper, we introduce a generalized graph-theoretic…

Quantum Physics · Physics 2026-03-03 Wesley Lewis , Darsh Pareek , Umesh Kumar , Ravi Janjam

We present an efficient tensor-network based algorithm for finding the optimal adaptive quantum channel discrimination strategies inspired by recently developed numerical methods in quantum metrology to find the optimal adaptive channel…

Quantum Physics · Physics 2026-02-11 Stanisław Sieniawski , Rafał Demkowicz-Dobrzański

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

In quantum information, most information processing processes involve quantum channels. One manifestation of a quantum channel is quantum operation acting on quantum states. The coherence of quantum operations can be considered as a quantum…

Quantum Physics · Physics 2022-11-23 Xiaorong Wang , Ting Gao , Fengli Yan

Simulating quantum physical processes has been one of the major motivations for quantum information science. Quantum channels, which are completely positive and trace preserving processes, are the standard mathematical language to describe…

Quantum Physics · Physics 2024-02-01 Hang Li , Kai Wang , Shijie Wei , Fan Yang , Xinyu Chen , Barry C. Sanders , Dong-Sheng Wang , Gui-Lu Long

In quantum technologies, quantum channels are essential elements for the transmission of quantum states. The action of a quantum channel usually introduces noise in the quantum state and thereby reduces the information contained in it.…

Quantum Physics · Physics 2026-04-10 Arindam Mitra , Jatin Ghai

Is it always possible to explain random stochastic transitions between states of a finite-dimensional system as arising from the deterministic quantum evolution of the system? If not, then what is the minimal amount of randomness required…

Quantum Physics · Physics 2018-05-16 Kamil Korzekwa , Stanisław Czachórski , Zbigniew Puchała , Karol Życzkowski

Quantum channels function as the operational primitives of quantum theory, while superchannels describe the most general transformations acting upon them. Yet the prevailing framework for superchannels is both internally inconsistent, owing…

Quantum Physics · Physics 2025-12-03 Yunlong Xiao

We propose a general method to operationally quantify the resourcefulness of quantum channels via channel discrimination, an important information processing task. A main result is that the maximum success probability of distinguishing a…

Quantum Physics · Physics 2020-03-04 Lu Li , Kaifeng Bu , Zi-Wen Liu

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

The data processing inequality is the most basic requirement for any meaningful measure of information. It essentially states that distinguishability measures between states decrease if we apply a quantum channel and is the centerpiece of…

Quantum Physics · Physics 2022-11-30 Christoph Hirche , Cambyse Rouzé , Daniel Stilck França

We obtain an explicit characterization of linear maps, in particular, quantum channels, which are covariant with respect to an irreducible representation ($U$) of a finite group ($G$), whenever $U \otimes U^c$ is simply reducible (with…

Quantum Physics · Physics 2017-05-26 Marek Mozrzymas , Michał Studziński , Nilanjana Datta

Many fundamental and key objects in quantum mechanics are linear mappings between particular affine/linear spaces. This structure includes basic quantum elements such as states, measurements, channels, instruments, non-signalling channels…

Quantum Physics · Physics 2024-07-19 Simon Milz , Marco Túlio Quintino

Open Quantum Walks (OQW) are a type of quantum walk governed by the system's interaction with its environment. We explore the time evolution and the limit behavior of the OQW framework for Quantum Computation and show how we can represent…

Quantum Physics · Physics 2025-09-30 Pedro Linck Maciel , Nadja K. Bernardes

So far, there have been plenty of literatures on the metric in the space of probability distributions and quantum states. As for channels, however, only a little had been known. In this paper, we impose monotonicity by concatenation of…

Quantum Physics · Physics 2010-06-03 Keiji Matsumoto

We present a general model for quantum channels with memory, and show that it is sufficiently general to encompass all causal automata: any quantum process in which outputs up to some time t do not depend on inputs at times t' > t can be…

Quantum Physics · Physics 2009-11-11 Dennis Kretschmann , Reinhard F. Werner

The quantum channel-state duality permits the characterization of a quantum process through a quantum state, referred to as a Choi state. This characteristic serves as the impetus for the quantum computing paradigm that utilizes Choi states…

Quantum Physics · Physics 2025-04-03 Y. -D. Liu , D. -S. Wang