Relation between full NEGF, non-Markovian and Markovian transport equations

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F21%3A10471289" target="_blank" >RIV/00216208:11320/21:10471289 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68378271:_____/21:00547740

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=Hwv5.UQNwF" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=Hwv5.UQNwF</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1140/epjs/s11734-021-00109-w" target="_blank" >10.1140/epjs/s11734-021-00109-w</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Relation between full NEGF, non-Markovian and Markovian transport equations

Popis výsledku v původním jazyce

This article addresses the problem of an efficient description of the transient electron transport in (primarily small open) quantum systems out of equilibrium. It provides an overview and critical review of the use of causal Ansatzes with the accent on derivation of (quantum) transport equations from the standard Kadanoff-Baym (KB) equations for the non-equilibrium Green&apos;s functions (NEGF). The family of causal Ansatzes originates from the well-known Generalized Kadanoff-Baym Ansatz (GKBA). The Ansatz technique has been fairly successful in practice. Recently, the scope of the method has been extended towards more &quot;difficult&quot; cases and its success can be assessed more precisely. This general picture is demonstrated and analyzed in detail for a variant of the generic molecular island model, an Anderson impurity linked between two bulk metallic leads by tunneling junctions. First, the KB equations are reduced to a non-Markovian generalized master equation (GME) by means of a general causal Ansatz. Further reduction to a Markovian master equation is achieved by partly relaxing the strictly causal character of the theory. For the model narrowed down to ferromagnetic leads, the transient currents are spin polarized and the tunneling functions have a complex spectral structure. This has prompted deriving explicit conditions for the use of an Ansatz. To extend the applicability range of the GME, approximate vertex corrections to the Ansatz were introduced and used with success. Finally, the relation of the GME description to possible non-equilibrium generalizations of the fluctuation-dissipation theorem is shown, extended beyond the present model within the NEGF formalism and physically interpreted in terms of a simplified kinetic theory of non-equilibrium electrons in open quantum systems.

Název v anglickém jazyce

Relation between full NEGF, non-Markovian and Markovian transport equations

Popis výsledku anglicky

This article addresses the problem of an efficient description of the transient electron transport in (primarily small open) quantum systems out of equilibrium. It provides an overview and critical review of the use of causal Ansatzes with the accent on derivation of (quantum) transport equations from the standard Kadanoff-Baym (KB) equations for the non-equilibrium Green&apos;s functions (NEGF). The family of causal Ansatzes originates from the well-known Generalized Kadanoff-Baym Ansatz (GKBA). The Ansatz technique has been fairly successful in practice. Recently, the scope of the method has been extended towards more &quot;difficult&quot; cases and its success can be assessed more precisely. This general picture is demonstrated and analyzed in detail for a variant of the generic molecular island model, an Anderson impurity linked between two bulk metallic leads by tunneling junctions. First, the KB equations are reduced to a non-Markovian generalized master equation (GME) by means of a general causal Ansatz. Further reduction to a Markovian master equation is achieved by partly relaxing the strictly causal character of the theory. For the model narrowed down to ferromagnetic leads, the transient currents are spin polarized and the tunneling functions have a complex spectral structure. This has prompted deriving explicit conditions for the use of an Ansatz. To extend the applicability range of the GME, approximate vertex corrections to the Ansatz were introduced and used with success. Finally, the relation of the GME description to possible non-equilibrium generalizations of the fluctuation-dissipation theorem is shown, extended beyond the present model within the NEGF formalism and physically interpreted in terms of a simplified kinetic theory of non-equilibrium electrons in open quantum systems.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10300 - Physical sciences

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2021

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

European Physical Journal: Special Topics

ISSN

1951-6355

e-ISSN

1951-6401

Svazek periodika

230

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

38

Strana od-do

771-808

Kód UT WoS článku

000645475400001

EID výsledku v databázi Scopus

2-s2.0-85105473618