| Autor: |
Murray, Matthias, Shinaoka, Hiroshi, Werner, Philipp |
| Rok vydání: |
2023 |
| Předmět: |
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| Zdroj: |
Phys. Rev. B 109, 165135 (2024) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1103/PhysRevB.109.165135 |
| Popis: |
The nonequilibrium Green's function formalism provides a versatile and powerful framework for numerical studies of nonequilibrium phenomena in correlated many-body systems. For calculations starting from an equilibrium initial state, a standard approach consists of discretizing the Kadanoff-Baym contour and implementing a causal time-stepping scheme in which the self-energy of the system plays the role of a memory kernel. This approach becomes computationally expensive at long times, because of the convolution integrals and the large amount of computer memory needed to store the Green's functions. A recent idea for the compression of nonequilibrium Green's functions is the quantics tensor train representation. Here, we explore this approach by implementing equilibrium and nonequilibrium simulations of the two-dimensional Hubbard model with a second-order weak-coupling approximation to the self-energy. We show that calculations with compressed two-time functions are possible without any loss of accuracy, and that the quantics tensor train implementation shows a much improved scaling of the computational effort and memory demand with the length of the time contour. |
| Databáze: |
arXiv |
| Externí odkaz: |
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