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Related papers: Nonequilibrium spin-boson model: from weak to stro…

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We provide a systematic approach to compute different kinds of non-equilibrium Green's functions for open quantum systems which are essentially two-point correlation functions in time. We reveal that the definition of Green's functions…

Statistical Mechanics · Physics 2023-09-08 Katha Ganguly , Bijay Kumar Agarwalla

We derive a general expression for the electron nonequilibrium (NE) distribution function in the context of steady state quantum transport through a two-terminal nanodevice with interaction. The central idea for the use of NE distributions…

Mesoscale and Nanoscale Physics · Physics 2014-02-26 H. Ness

We discuss how the crossovers in models like spin-boson model are changed by adding the coupling of the central spin to localised modes- the latter modelled as a 'spin bath'. These modes contain most of the environmental entropy and energy…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 P. C. E. Stamp , I. S. Tupitsyn

We generalize time-evolving matrix product operators method to nonequilibrium quantum transport problems. The nonequilibrium current is obtained via numerical differentiation of the generating functional which is represented as a tensor…

Mesoscale and Nanoscale Physics · Physics 2023-03-23 Ruofan Chen

A novel approximation scheme is proposed to describe the dynamics of the spin-boson problem. Being nonperturbative in the coupling strength nor in the tunneling frequency, it gives reliable results over a wide regime of temperatures and…

Statistical Mechanics · Physics 2009-11-13 Francesco Nesi , Elisabetta Paladino , Michael Thorwart , Milena Grifoni

We use the effective-mass approximation and the density-functional theory with the local-density approximation for modeling two-dimensional nano-structures connected phase-coherently to two infinite leads. Using the non-equilibrium Green's…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Paula Havu , Ville Havu , Martti Puska , Risto Nieminen

In this work, we study the low-energy properties of the spin-boson model (SBM), which describes the dynamics of a 1/2 spin associated with a thermostat characterized by a power law spectral density, $f(\omega)\propto \omega^s$. The…

Statistical Mechanics · Physics 2025-07-15 M. G. Vasin , S. V. Remizov , A. A. Elistratov

Employing a combination of a sign-free Monte Carlo approach and nonequilibrium Green's function techniques, we study nonequilibrium charge transport in a model heterostructure, where a two-dimensional spin-less Falicov-Kimball system is…

Strongly Correlated Electrons · Physics 2019-05-03 Martin Žonda , Michael Thoss

Quantum transport through single molecules is essentially affected by molecular vibrations. We investigate the behavior of the prototype single-level model with intermediate electron-vibron coupling and arbitrary coupling to the leads. We…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Dmitry A. Ryndyk , Gianaurelio Cuniberti

We introduce a simple ansatz for the wavefunction of a many-body system based on coupled forward and backward-propagating semiclassical trajectories. This method is primarily aimed at, but not limited to, treating nonequilibrium dynamics in…

Chemical Physics · Physics 2018-05-01 Shunsuke A. Sato , Aaron Kelly , Angel Rubio

We investigate the spin-boson model's dynamical and thermodynamic features in the weak coupling regime using the weak coupling spin-boson (WCSB) and phase covariant (PC) master equations. Both unital (pure dephasing) and non-unital…

Quantum Physics · Physics 2025-12-01 Mahima Yadav , Devvrat Tiwari , Subhashish Banerjee

We study the properties of a refined weak coupling limit that preserves complete positivity in order to describe non-Markovian dynamics in the spin-boson model. With this tool, we show the system presents a rich and new non-Markovian…

Quantum Physics · Physics 2017-04-10 Ángel Rivas

The quantum dynamics of correlated fermionic or bosonic many-body systems following external excitation can be successfully studied using nonequilibrium Green functions (NEGF) or reduced density matrix methods. Approximations are introduced…

Strongly Correlated Electrons · Physics 2023-12-27 Erik Schroedter , Björn Jakob Wurst , Jan-Philip Joost , Michael Bonitz

We study in a unified manner the dissipative dynamics and the transfer of heat in the two-bath spin-boson model. We use the Bloch-Redfield (BR) formalism, valid in the very weak system-bath coupling limit, the noninteracting-blip…

Mesoscale and Nanoscale Physics · Physics 2015-05-05 Nazim Boudjada , Dvira Segal

In a recent Letter [Balzer \textit{et al.}, Phys. Rev. Lett. \textbf{121}, 267602 (2018)] it was demonstrated that ions impacting a correlated graphene cluster can excite strongly nonequilibrium states. In particular, this can lead to an…

Strongly Correlated Electrons · Physics 2022-04-27 Lotte Borkowski , Niclas Schlünzen , Jan Philip Joost , Franziska Reiser , Michael Bonitz

Optimal control theory is implemented with fully converged hierarchical equations of motion (HEOM) describing the time evolution of an open system density matrix strongly coupled to the bath in a spin-boson model. The populations of the…

We explore the behavior in time of the energy exchange between a system of interest and its environment, together with its relationship to the non-Markovianity of the system dynamics. In order to evaluate the energy exchange we rely on the…

Quantum Physics · Physics 2016-01-26 Giacomo Guarnieri , Chikako Uchiyama , Bassano Vacchini

We consider resonant transport through a molecular quantum dot coupled to a local vibration mode. Applying the non-equilibrium Green function technique in the polaron representation, we develop a non-perturbative scheme to calculate the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Alex Zazunov , Thierry Martin

A continuous sequence of infinitesimal unitary transformations is used to diagonalize the quantum sine-Gordon model for \beta^2\in(2\pi,\infty). This approach can be understood as an extension of perturbative scaling theory since it links…

Statistical Mechanics · Physics 2009-10-31 Stefan Kehrein

Coherent electronic transport through a molecular device is studied using non-equilibrium Green's function (NEGF) formalism. Such device is made of a short linear wire which is connected to para- and ferromagnetic electrodes. Molecule…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Kamil Walczak
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