Year: 2025
Type: article
Abstract: One of the challenges in diagrammatic simulations of nonequilibrium phenomena in lattice models is the large memory demand for storing momentum-dependent two-time correlation functions. This problem can be overcome with the recently introduced quantics tensor train (QTT) representation of multivariable functions. Here, we demonstrate nonequilibrium Green's function simulations within the GW and Migdal approximations with high momentum resolution, up to times which exceed the capabilities of standard implementations and are long enough to study, e.g., transient Floquet physics during multicycle electric field pulses and thermalization dynamics. The self-consistent calculation on the three-leg Kadanoff-Baym contour is fully self-contained, employing only QTT-compressed functions and input functions which are either generated directly in QTT form or obtained via quantics tensor cross interpolation.
Source: Physical Review Letters
DOI: 10.1103/dxfb-b3l5
Institutions: University of Fribourg, Saitama University
Language: English
Topic: Quantum many-body systems
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: Development of the nonequilibrium Green's function method utilizing space-time compression techniques and its application to long-time dynamics calculations, 2粒子レベルの量子埋め込み理論に基づく新規第一原理計算手法の開発と実証, スパースモデリングを用いた固体の革新的量子計算技術の開発, Extension and demonstration of two-particle-level computational theory based on dimensionality reduction to nonlocal electron correlation effects, G4910293609, G6430560525, Correlated multi-orbital lattice systems, Control theory of photo-induced dynamics in correlated electron systems utilizing phonon-excitation, G993971353
OpenAlex ID: W4416735376