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We derived quantum trajectories for a system interacting with the environment prepared in a continuous mode single photon state as the limit of discrete filtering model with an environment defined as series of independent qubits prepared…

Quantum Physics · Physics 2020-02-11 Anita Dabrowska , Gniewomir Sarbicki , Dariusz Chruscinski

We derive sufficient conditions for the memory kernel which guarantee legitimate (completely positive and trace-preserving) dynamical map. It turns out that these conditions provide a natural parameterizations of the dynamical map being a…

Quantum Physics · Physics 2016-08-24 Dariusz Chruściński , Andrzej Kossakowski

A linear map between matrix spaces is positive if it maps positive semidefinite matrices to positive semidefinite ones, and is called completely positive if all its ampliations are positive. In this article quantitative bounds on the…

Functional Analysis · Mathematics 2019-07-10 Igor Klep , Scott McCullough , Klemen Šivic , Aljaž Zalar

We use the Koashi-Imoto decomposition of the degrees of freedom of joint system-environment initial states to investigate the reduced dynamics. We show that a subset of joint system-environment initial states guarantees completely positive…

Quantum Physics · Physics 2016-06-07 Xiao-Ming Lu

We study the influence of the preparation of an open quantum system on its reduced time evolution. In contrast to the frequently considered case of an initial preparation where the total density matrix factorizes into a product of a system…

Quantum Physics · Physics 2009-11-10 Karen M. Fonseca Romero , Peter Talkner , Peter Hänggi

In this work we investigate the relation between quantum measurements and decoherence, in order to formally express the necessity of the latter for obtaining an informative output from the former. To this aim, referring to the Von Neumann…

Quantum Physics · Physics 2015-06-23 Pietro Liuzzo-Scorpo , Alessandro Cuccoli , Paola Verrucchi

It is possible to prepare a composite qubit-environment system so that its time evolution will guarantee the conservation of a preselected qubit's observable. In general, this observable is not associated with a symmetry. The latter may not…

Quantum Physics · Physics 2013-05-24 Bartlomiej Gardas , Jerzy Dajka

This study investigates Hermitian linear maps, focusing on their decomposition into completely positive (CP) maps and their extensions to CP maps using auxiliary spaces. We derive a precise lower bound on the Hilbert-Schmidt norm of the…

Functional Analysis · Mathematics 2025-06-12 Mohsen Kian , Mohsen Rostamian Delavar

We consider a partial trace transformation which maps a multipartite quantum state to collection of local density matrices. We call this collection a mean field state. The necessary and sufficient conditions under which a mean field state…

Quantum Physics · Physics 2016-09-08 Sergey Bravyi

We derive stochastic master equation for a quantum system interacting with an environment prepared in a continuous-mode $N$-photon state. To determine the conditional evolution of the quantum system depending on continuous in time…

Quantum Physics · Physics 2020-02-11 Anita Dąbrowska , Gniewomir Sarbicki , Dariusz Chruściński

We study the dynamics of a two-level atom interacting with a Lorentzian structured reservoir considering initial system-environment correlations. It is shown that under strong system-reservoir coupling the dynamics of purity can determine…

Quantum Physics · Physics 2015-03-19 D. Z. Rossatto , T. Werlang , L. K. Castelano , C. J. Villas-Boas , F. F. Fanchini

New exact results about the nonequilibrium thermodynamics of open quantum systems at arbitrary timescales are obtained by considering all possible variations of initial conditions of a system, its environment, and correlations between them.…

Statistical Mechanics · Physics 2021-05-05 Paul M. Riechers , Mile Gu

In quantum information processing it may be possible to have efficient computation and secure communication beyond the limitations of classical systems. In a fundamental point of view, however, evolution of quantum systems by the laws of…

Quantum Physics · Physics 2017-09-21 Joonwoo Bae

We determine the total state dynamics of a dephasing open quantum system using the standard environment of harmonic oscillators. Of particular interest are random unitary approaches to the same reduced dynamics and system-environment…

Quantum Physics · Physics 2015-06-04 Ansgar Pernice , Julius Helm , Walter T. Strunz

State transformations in quantum mechanics are described by completely positive maps which are constructed from quantum channels. We call a finest sharp quantum channel a context. The result of a measurement depends on the context under…

Quantum Physics · Physics 2022-09-01 Stan Gudder

In this paper we demonstrate that any Markovian master equation defining a completely positive evolution for a quantum-classical hybrid state can always be written in terms of four basic coupling mechanisms. Each of them is characterized by…

Quantum Physics · Physics 2024-09-17 Adrián A. Budini

Quantum correlation can be created by a local operation from some initially classical states. We prove that the necessary and sufficient condition for a local trace-preserving channel to create quantum correlation is that it is not a…

Quantum Physics · Physics 2012-03-08 Xueyuan Hu , Heng Fan , D. L. Zhou , Wu-Ming Liu

Recently 't Hooft demonstrated that ``For any quantum system there exists at least one deterministic model that reproduces all its dynamics after prequantization''. An extension is presented here which covers quantum systems that are…

Quantum Physics · Physics 2009-11-13 Hans-Thomas Elze

Using the known possibility to associate the completely positive maps with density matrices and recent results on expressing the density matrices with sets of classical probability distributions of dichotomic random variables we construct…

Quantum Physics · Physics 2019-04-09 Ashot Avanesov , Vladimir I. Man'ko

We present a general analysis of the role of initial correlations between the open system and an environment on quantum dynamics of the open system.

Quantum Physics · Physics 2009-11-07 Peter Stelmachovic , Vladimir Buzek