Dresden 2020 – wissenschaftliches Programm
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TT 48.12: Poster
Mittwoch, 18. März 2020, 15:00–19:00, P2/4OG
Fast Nonequilibrium Green Functions simulations with GW selfenergies — •Christopher Makait, Niclas Schlünzen, Jan-Philip Joost, and Michael Bonitz — Institut für Theoretische Physik und Astrophysik, CAU Kiel, Germany
The Nonequilibrium Green Functions (NEGF) method is a powerful tool to compute time-dependent expectation values of single-particle observables in correlated quantum many-body systems. Its unfavorable Nt3-scaling with propagation time Nt could be reduced to Nt2 by introduction of the Generalized Kadanoff–Baym Ansatz (GKBA). Recently, an exact time-local (Nt1) reformulation of the GKBA, the G1–G2 scheme [3,4], has been found for various self energies, which makes this method viable for long time simulations.
In a general basis the G1–G2 scheme has a computationally expensive scaling with basis size (Nb5–Nb6). For the uniform electron gas (UEG) however, we found an advantageous Nb3Nt1 scaling for both second-order and GW selfenergies, which makes this scheme particularly interesting for this system. Here, we present first results of the application of the G1–G2 scheme to the UEG.
 L. P. Kadanoff, G. Baym, Quantum Statistical Mechanics (Benjamin, New York, 1962)
 P. Lipavský, V. Špička, B. Velický, Phys. Rev. B34, 6933 (1986)
 N. Schlünzen, Jan-Philip Joost, Michael Bonitz, submitted, arXiv:1909.11489 [cond-mat.str-el]
 M. Bonitz, Quantum Kinetic Theory (Springer, 2016)