Accelerating Nonequilibrium Green functions simulations with embedding selfenergies
| Title: | Accelerating Nonequilibrium Green functions simulations with embedding selfenergies |
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| Authors: | Balzer, Karsten, Schlünzen, Niclas, Ohldag, Hannes, Joost, Jan-Philip, Bonitz, Michael |
| Publication Year: | 2022 |
| Collection: | Condensed Matter Physics (Other) Quantum Physics |
| Subject Terms: | Condensed Matter - Strongly Correlated Electrons, Physics - Computational Physics, Quantum Physics |
| More Details: | Real-time nonequilibrium Green functions (NEGF) have been very successful to simulate the dynamics of correlated many-particle systems far from equilibrium. However, NEGF simulations are computationally expensive since the effort scales cubically with the simulation duration. Recently we have introduced the G1--G2 scheme that allows for a dramatic reduction to time-linear scaling [Schl\"unzen, Phys. Rev. Lett. 124, 076601 (2020); Joost et al., Phys. Rev. B 101, 245101 (2020)]. Here we tackle another problem: the rapid growth of the computational effort with the system size. In many situations where the system of interest is coupled to a bath, to electric contacts or similar macroscopic systems for which a microscopic resolution of the electronic properties is not necessary, efficient simplifications are possible. This is achieved by the introduction of an embedding selfenergy -- a concept that has been successful in standard NEGF simulations. Here, we demonstrate how the embedding concept can be introduced into the G1--G2 scheme, allowing us to drastically accelerate NEGF embedding simulations. The approach is compatible with all advanced selfenergies that can be represented by the G1--G2 scheme [as described in Joost et al., Phys. Rev. B 105, 165155 (2022)] and retains the memory-less structure of the equations and their time linear scaling. As a numerical illustration we investigate the charge transfer between a Hubbard nanocluster and an additional site which is of relevance for the neutralization of ions in matter. |
| Document Type: | Working Paper |
| DOI: | 10.1103/PhysRevB.107.155141 |
| Access URL: | http://arxiv.org/abs/2211.09615 |
| Accession Number: | edsarx.2211.09615 |
| Database: | arXiv |
| DOI: | 10.1103/PhysRevB.107.155141 |
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