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Real-time Green's function simulations of molecular junctions (open quantum systems) are typically performed by solving the Kadanoff-Baym equations (KBE). The KBE, however, impose a serious limitation on the maximum propagation time due to…

Mesoscale and Nanoscale Physics · Physics 2015-06-17 S. Latini , E. Perfetto , A. -M. Uimonen , R. van Leeuwen , G. Stefanucci

It is shown that the Kadanoff-Baym equations at consistent first-order gradient approximation reveal exact rather than approximate conservation laws related to global symmetries of the system. The conserved currents and energy-momentum…

Nuclear Theory · Physics 2011-08-12 J. Knoll , Yu. B. Ivanov , D. N. Voskresensky

The understanding of out-of-equilibrium fluctuation relations in small open quantum systems has been a focal point of research in recent years. In particular, for systems with adiabatic time-dependent driving, it was shown that the…

Mesoscale and Nanoscale Physics · Physics 2021-02-03 Roman-Pascal Riwar , Janine Splettstoesser

We propose a description of nonequilibrium systems via a simple protocol that combines exchange-correlation potentials from density functional theory with self-energies of many-body perturbation theory. The approach, aimed to avoid double…

Strongly Correlated Electrons · Physics 2016-06-15 M. Hopjan , D. Karlsson , S. Ydman , C. Verdozzi , C. -O. Almbladh

We present in detail a method we recently introduced (PRL. 103, 176404 (2009)) to describe finite systems in and out of equilibrium, where the evolution in time is performed via the Kadanoff-Baym Equations (KBE) within Many-Body…

Strongly Correlated Electrons · Physics 2010-04-22 M. Puig von Friesen , C. Verdozzi , C. -O. Almbladh

Understanding time-resolved quantum transport is crucial for developing next-generation quantum technologies, particularly in nano- and molecular junctions subjected to time-dependent perturbations. Traditional steady-state approaches to…

Mesoscale and Nanoscale Physics · Physics 2025-10-16 R. Tuovinen , Y. Pavlyukh

The generalized Kadanoff-Baym ansatz (GKBA) is an approximation to the Kadanoff-Baym equations (KBE), that neglects certain memory effects that contribute to the Green's function at non-equal times. Here we present arguments and numerical…

Computational Physics · Physics 2023-09-06 Cian C. Reeves , Yuanran Zhu , Chao Yang , Vojtech Vlcek

Time-dependent nonequilibrium Green's functions are used to study electron transport properties in a device consisting of two linear chain leads and a time-dependent interleads coupling that is switched on non-adiabatically. We derive a…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 Eduardo C. Cuansing , Gengchiau Liang

The calculation of quantum canonical time correlation functions is considered in this paper. Transport properties, such as diffusion and reaction rate coefficients, can be determined from time integrals of these correlation functions.…

Other Condensed Matter · Physics 2010-11-17 Ali Nassimi , Raymond Kapral

By propagating the many-body Schr\"odinger equation, we determine the exact time-dependent Kohn-Sham potential for a system of strongly correlated electrons which undergo field-induced tunneling. Numerous features are entirely absent from…

Strongly Correlated Electrons · Physics 2021-01-15 Matthew J. P. Hodgson , James D. Ramsden , Jacob B. J. Chapman , Piers Lillystone , Rex W Godby

Consider a quantum dot coupled to two semi-infinite one-dimensional leads at thermal equilibrium. We turn on adiabatically a bias between the leads such that there exists exactly one discrete eigenvalue both at the beginning and at the end…

Mathematical Physics · Physics 2015-07-23 Horia D. Cornean , Arne Jensen , Gheorghe Nenciu

We demonstrate the remnant presence of {\em initial} correlations in the {\em steady-state} electrical current flowing between low-dimensional interacting leads. The leads are described as Luttinger liquids and electrons can tunnel via a…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 E. Perfetto , G. Stefanucci , M. Cini

We investigate the nonstationary electronic transport in noninteracting nanostructures driven by a finite bias and time-dependent signals applied at their contacts to the leads. The systems are modelled by a tight-binding Hamiltonian and…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Valeriu Moldoveanu , Vidar Gudmundsson , Andrei Manolescu

Thermodynamics of quantum systems out-of-equilibrium is very important for the progress of quantum technologies, however, the effects of many body interactions and their interplay with temperature, different drives and dynamical regimes is…

Quantum Physics · Physics 2020-01-08 A. H. Skelt , K. Zawadzki , I. D'Amico

Using non-equilibrium Green's functions combined with many-body perturbation theory, we have calculated steady-state densities and currents through short interacting chains subject to a finite electric bias. By using a steady-state…

Mesoscale and Nanoscale Physics · Physics 2016-04-18 Daniel Karlsson , Claudio Verdozzi

Adiabatic theorem and non-adiabatic corrections have been widely applied in modern quantum technology. Recently, non-adiabatic linear response theory has been developed to probe the many-body correlations in closed systems. In this work, we…

Quantum Gases · Physics 2025-09-10 Xiaotian Nie , Wei Zheng

We analyze the time-evolution of a quantum dot which is proximized by a large-gap superconductor and weakly probed using the charge and heat currents into a wide-band metal electrode. We map out the full time dependence of these currents…

Mesoscale and Nanoscale Physics · Physics 2023-05-23 Lara C. Ortmanns , Janine Splettstoesser , Maarten R. Wegewijs

Understanding the dynamics of nonequilibrium quantum many-body systems is an important research topic in a wide range of fields across condensed matter physics, quantum optics, and high-energy physics. However, numerical studies of…

Strongly Correlated Electrons · Physics 2024-12-11 Yuanran Zhu , Jia Yin , Cian C. Reeves , Chao Yang , Vojtech Vlcek

Correlation effects in the transport properties of a single quantum level coupled to electron reservoirs are discussed theoretically using a non-equilibrium Green functions approach. Our method is based on the introduction of a second-order…

Condensed Matter · Physics 2016-08-14 A. Levy Yeyati , A. Martín-Rodero , F. Flores

A general analytical theory of temporal relaxation processes in isolated quantum systems with many degrees of freedom is elaborated, which unifies and substantially amends several previous approximations. Specifically, the Fourier transform…

Statistical Mechanics · Physics 2019-05-09 Peter Reimann