Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Models for quantum memory channels

Stefano Mancini

Published Jan 1, 2006• 0 citations
OpenAlex

Abstract

We discuss a couple of models aimed to describe memory effects in quantum channels. We start from a rather intuitive model and arrive to a more abstract one which turns out to be more general.

Related papers

Models for Quantum Memory Channels

Stefano Mancini

We discuss a couple of models aimed to describe memory effects in quantum channels. We start from a rather intuitive model and arrive to a more abstract one which turns out to be more general.

Journal of Physics Conference Series•Apr 1, 2006•4 citations

Quantum Memory Channels in Quantum Optics

Tomáš Rybár, Mário Ziman, Vladimír Bu_ek

CRC Press eBooks•Dec 14, 2012•0 citations

Quantum Channels with Memory

Tomáš Rybár

Abstract Quantum memory channels represent a very general, yet simple and comprehensible model for causal processes. As such they have attracted considerable research interest, mostly aimed on their transfer capabilities and structure properties. Most notably it was shown that memory channels can be implemented via physically naturally motivated collision models. We also define the concept of repeatable channels and show that only unital channels can be implemented repeatably with pure memory channels. In the special case of qubit channels we also show that every unital qubit channel has a repeatable implementation. We also briefly explore the possibilities of stroboscopical simulation of channels and show that all random unitary channels can be stroboscopically simulated. Particularly in qubit case, all indivisible qubit channels are also random unitary, hence for qubit all indivisible channels can be stroboscopically simulated. Memory channels also naturally capture the framework of correlated experiments. We develop methods to gather and interpret data obtained in such setting and in detail examine the two qubit case. We also show that for control unitary interactions the measured data will never contradict a simple unitary evolution. Thus no memory effects can be spotted then.

Acta Physica Slovaca Reviews and Tutorials•Nov 30, 2012•4 citations

Unraveling-paired dynamical maps recover the input of quantum channels

Brecht Donvil, Paolo Muratore-Ginanneschi

Abstract We explore algebraic and dynamical consequences of unraveling general time-local master equations. We show that the ‘influence martingale’, the paramount ingredient of a recently discovered unraveling framework, pairs any time-local master equation with a one parameter family of Lindblad–Gorini–Kossakowski–Sudarshan master equations. At any instant of time, the variance of the influence martingale provides an upper bound on the Hilbert–Schmidt distance between solutions of paired master equations. Finding the lowest upper bound on the variance of the influence martingale yields an explicit criterion of ‘optimal pairing’. The criterion independently retrieves the measure of isotropic noise necessary for the structural physical approximation of the flow the time-local master equation with a completely positive flow. The optimal pairing also allows us to invoke a general result on linear maps on operators (the ‘commutant representation’) to embed the flow of a general master equation in the off-diagonal corner of a completely positive semi-group which in turn solves a time-local master equation that we explicitly determine. We use the embedding to reverse a completely positive evolution, a quantum channel, to its initial condition thereby providing a protocol to preserve quantum memory against decoherence. We thus arrive at a model of continuous-time error correction by a quantum channel.

arXiv:2209.08958•New Journal of Physics•May 1, 2023•6 citations

Quantum Memory Channels in Quantum Optics

Tomáš Rybár, Mário Ziman, Vladimír Bužek

CRC Press eBooks•Oct 8, 2018•0 citations

Teaching Einsteinian physics at schools: part 2, models and analogies for quantum physics

T. Kaur, D. G. Blair, John Moschilla +1 more

Abstract The Einstein-First project approaches the teaching of Einsteinian physics through the use of physical models and analogies. This paper presents an approach to the teaching of quantum physics which begins by emphasising the particle-nature of light through the use of toy projectiles to represent photons. This allows key concepts including the spacing between photons, and photon momentum to be introduced. This in-turn allows an intuitive understanding of the uncertainty principle. We present optical interference in the context of individual photons, using actual videos showing the development of images one at a time. This enables simple laser interference experiments to be interpreted through the statistical arrival of photons. The wave aspects of quantum phenomenon are interpreted in terms of the wavelike nature of the arrival probabilities.

arXiv:1707.03728•Physics Education•Sep 22, 2017•32 citations
Abstract Quantum memory channels represent a very general, yet simple and comprehensible model for causal processes. As such they have attracted considerable research interest, mostly aimed on their transfer capabilities and structure properties. Most notably it was shown that memory channels can be implemented via physically naturally motivated collision models. We also define the concept of repeatable channels and show that only unital channels can be implemented repeatably with pure memory channels. In the special case of qubit channels we also show that every unital qubit channel has a repeatable implementation. We also briefly explore the possibilities of stroboscopical simulation of channels and show that all random unitary channels can be stroboscopically simulated. Particularly in qubit case, all indivisible qubit channels are also random unitary, hence for qubit all indivisible channels can be stroboscopically simulated. Memory channels also naturally capture the framework of correlated experiments. We develop methods to gather and interpret data obtained in such setting and in detail examine the two qubit case. We also show that for control unitary interactions the measured data will never contradict a simple unitary evolution. Thus no memory effects can be spotted then.
Abstract We explore algebraic and dynamical consequences of unraveling general time-local master equations. We show that the ‘influence martingale’, the paramount ingredient of a recently discovered unraveling framework, pairs any time-local master equation with a one parameter family of Lindblad–Gorini–Kossakowski–Sudarshan master equations. At any instant of time, the variance of the influence martingale provides an upper bound on the Hilbert–Schmidt distance between solutions of paired master equations. Finding the lowest upper bound on the variance of the influence martingale yields an explicit criterion of ‘optimal pairing’. The criterion independently retrieves the measure of isotropic noise necessary for the structural physical approximation of the flow the time-local master equation with a completely positive flow. The optimal pairing also allows us to invoke a general result on linear maps on operators (the ‘commutant representation’) to embed the flow of a general master equation in the off-diagonal corner of a completely positive semi-group which in turn solves a time-local master equation that we explicitly determine. We use the embedding to reverse a completely positive evolution, a quantum channel, to its initial condition thereby providing a protocol to preserve quantum memory against decoherence. We thus arrive at a model of continuous-time error correction by a quantum channel.
Abstract The Einstein-First project approaches the teaching of Einsteinian physics through the use of physical models and analogies. This paper presents an approach to the teaching of quantum physics which begins by emphasising the particle-nature of light through the use of toy projectiles to represent photons. This allows key concepts including the spacing between photons, and photon momentum to be introduced. This in-turn allows an intuitive understanding of the uncertainty principle. We present optical interference in the context of individual photons, using actual videos showing the development of images one at a time. This enables simple laser interference experiments to be interpreted through the statistical arrival of photons. The wave aspects of quantum phenomenon are interpreted in terms of the wavelike nature of the arrival probabilities.