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Understanding and optimizing the relaxation dynamics of many-body systems is essential both for foundational studies in quantum thermodynamics and for applications such as quantum simulation and quantum computing. Efficient preparation of…

Recently, a lot of attention has been devoted to finding physically realisable operations that realise as closely as possible certain desired transformations between quantum states, e.g. quantum cloning, teleportation, quantum gates, etc.…

Quantum Physics · Physics 2013-04-25 K. Audenaert , B. De Moor

For quantum transport through mesoscopic system, a quantum master equation approach is developed in terms of compact expressions for the transport current and the reduced density matrix of the system. The present work is an extension of…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Xin-Qi Li , Jun-Yan Luo , Yong-Gang Yang , Ping Cui , YiJing Yan

Polaron-transformed quantum master equation (PQME) offers a unified framework to describe the dynamics of quantum systems in both limits of weak and strong couplings to environmental degrees of freedom. Thus, PQME serves as an efficient…

Quantum Physics · Physics 2026-01-01 Seogjoo J. Jang

Positivity or the stronger notion of complete positivity, and contextuality are central properties of quantum dynamics. In this work, we demonstrate that a physical unitary-universe dilation model could be employed to characterize the…

Quantum Physics · Physics 2013-03-22 Song Cheng , Dongsheng Wang

The study of quantum thermal machines, and more generally of open quantum systems, often relies on master equations. Two approaches are mainly followed. On the one hand, there is the widely used, but often criticized, local approach, where…

Energy extraction from quantum batteries by means of completely positive trace-preserving (CPTP) maps leads to the concept of CPTP-local passive states, which identify bipartite states from which no energy can be squeezed out by applying…

Quantum Physics · Physics 2024-06-19 Aparajita Bhattacharyya , Kornikar Sen , Ujjwal Sen

We analytically derive the exact -- though formal -- master equation for a two-level quantum system (qubit) interacting with a bosonic environment within the rotating-wave approximation, assuming the environment is initially in an arbitrary…

Quantum Physics · Physics 2025-10-16 Hiromichi Nakazato , Saverio Pascazio

In this paper, we generalize the quantum Brownian motion to include momentum-dependent system-environment couplings. The conventional QBM model corresponds to the spacial case $W_k = V_k$. The generalized QBM is more complicated but the…

Quantum Physics · Physics 2023-01-20 Yu-Wei Huang , Wei-Min Zhang

The equation for the quantum motion of a Brownian particle in a gaseous environment is derived by means of S-matrix theory. This quantum version of the linear Boltzmann equation accounts non-perturbatively for the quantum effects of the…

Quantum Physics · Physics 2007-05-23 Klaus Hornberger

We investigate the equilibration and thermalization properties of quantum systems interacting with a finite dimensional environment. By exploiting the concept of time averaged states, we introduce a completely positive map which allows to…

Quantum Physics · Physics 2012-11-27 A. Smirne , E. -M. Laine , H. -P. Breuer , J. Piilo , B. Vacchini

We show how the quantum analog of the Fokker-Planck equation for describing Brownian motion can be obtained as the diffusive limit of the quantum linear Boltzmann equation. The latter describes the quantum dynamics of a tracer particle in a…

Quantum Physics · Physics 2007-12-20 Bassano Vacchini , Klaus Hornberger

An equilibrium state can be represented by a pure quantum state, which we call a thermal pure quantum (TPQ) state. We propose a new TPQ state and a simple method of obtaining it. A single realization of the TPQ state suffices for…

Statistical Mechanics · Physics 2012-06-18 Sho Sugiura , Akira Shimizu

We build an exact framework to evaluate heat, energy, and particle transport between Gaussian reservoirs mediated by a quadratic quantum system. By combining full counting statistics with newly developed non-Markovian master equation…

Quantum Physics · Physics 2026-02-25 Guglielmo Pellitteri , Vittorio Giovannetti , Vasco Cavina

We present a rigorous approach, based on the concept of continuous thermomajorisation, to algorithmically characterise the full set of energy occupations of a quantum system accessible from a given initial state through weak interactions…

Quantum Physics · Physics 2022-08-08 Kamil Korzekwa , Matteo Lostaglio

We study the relaxation of a quantum system towards the thermal equilibrium using tools developed within the context of quantum information theory. We consider a model in which the system is a qubit, and reaches equilibrium after several…

Quantum Physics · Physics 2009-11-07 Valerio Scarani , Mario Ziman , Peter Stelmachovic , Nicolas Gisin , Vladimir Buzek

Starting from a microscopic theory, we derive a master equation for a harmonic oscillator coupled to a bath of non-interacting oscillators. We follow a non-perturbative approach, proposed earlier by us for the free Brownian particle. The…

Quantum Physics · Physics 2013-05-29 Jishad Kumar , S. Sinha , P. A. Sreeram

Quantum thermalization describes how closed quantum systems can effectively reach thermal equilibrium, resolving the apparent incongruity between the reversibility of Schr\"odinger's equation and the second law of thermodynamics. Despite…

Quantum Physics · Physics 2026-01-08 Saúl Pilatowsky-Cameo , Soonwon Choi

We consider the master equation of quantum Brownian motion and with the application of the group invariant transformation we show that there exists a surface on which the solution of the master equation is given by an autonomous…

Mathematical Physics · Physics 2016-12-23 R. Sinuvasan , A. Paliathanasis , R. M. Morris , P. G. L. Leach

We derive a completely positive post-Markovian master equation (PMME) from a microscopic Markovian collisional model framework, incorporating bath memory effects via a probabilistic single-shot measurement approach. This phenomenological…

Quantum Physics · Physics 2024-11-27 Tanmay Saha , Sahil , K. P. Athulya , Sibasish Ghosh