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RESEARCH PRODUCT
The generalized Kadanoff-Baym ansatz with initial correlations
Enrico PerfettoGianluca StefanucciDaniel KarlssonRobert Van Leeuwensubject
PhysicsKadanoff-Baym ansatzStrongly Correlated Electrons (cond-mat.str-el)ta114many-body theoryFOS: Physical sciencesNon-equilibrium thermodynamics02 engineering and technologyGreen's functionCondensed Matter::Mesoscopic Systems and Quantum Hall Effect021001 nanoscience & nanotechnology01 natural sciencesSettore FIS/03 - Fisica della MateriaCondensed Matter - Strongly Correlated ElectronsImproved performanceFormalism (philosophy of mathematics)0103 physical sciencesExternal fieldStatistical physicskvanttifysiikka010306 general physics0210 nano-technologyAdiabatic processQuantumAnsatzdescription
Within the non-equilibrium Green's function (NEGF) formalism, the Generalized Kadanoff-Baym Ansatz (GKBA) has stood out as a computationally cheap method to investigate the dynamics of interacting quantum systems driven out of equilibrium. Current implementations of the NEGF--GKBA, however, suffer from a drawback: real-time simulations require {\em noncorrelated} states as initial states. Consequently, initial correlations must be built up through an adiabatic switching of the interaction before turning on any external field, a procedure that can be numerically highly expensive. In this work, we extend the NEGF--GKBA to allow for {\em correlated} states as initial states. Our scheme makes it possible to efficiently separate the calculation of the initial state from the real-time simulation, thus paving the way for enlarging the class of systems and external drivings accessible by the already successful NEGF--GKBA. We demonstrate the accuracy of the method and its improved performance in a model donor-acceptor dyad driven out of equilibrium by an external laser pulse.
year | journal | country | edition | language |
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2018-06-14 | Physical Review B |