Stochastic Real-Time Second-Order Green's Function Theory for Neutral Excitations in Molecules and Nanostructures
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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866917574915129344 |
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| author | Mejía, Leopoldo Yin, Jia Reichman, David R. Baer, Roi Yang, Chao Rabani, Eran |
| author_facet | Mejía, Leopoldo Yin, Jia Reichman, David R. Baer, Roi Yang, Chao Rabani, Eran |
| contents | We present a real-time second-order Green's function (GF) method for computing excited states in molecules and nanostructures, with a computational scaling of $O(N_{\rm e}^3$), where $N_{\rm e}$ is the number of electrons. The cubic scaling is achieved by adopting the stochastic resolution of the identity to decouple the 4-index electron repulsion integrals (ERI). To improve the time-propagation and the spectral resolution, we adopt the dynamic mode decomposition (DMD) technique and assess the accuracy and efficiency of the combined approach for a chain of hydrogen dimer molecules of different lengths. We find that the stochastic implementation accurately reproduces the deterministic results for the electronic dynamics and excitation energies. Furthermore, we provide a detailed analysis of the statistical errors, bias, and long-time extrapolation. Overall, the approach offers an efficient route to investigate excited states in extended systems with open or closed boundary conditions. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2303_06874 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Stochastic Real-Time Second-Order Green's Function Theory for Neutral Excitations in Molecules and Nanostructures Mejía, Leopoldo Yin, Jia Reichman, David R. Baer, Roi Yang, Chao Rabani, Eran Chemical Physics We present a real-time second-order Green's function (GF) method for computing excited states in molecules and nanostructures, with a computational scaling of $O(N_{\rm e}^3$), where $N_{\rm e}$ is the number of electrons. The cubic scaling is achieved by adopting the stochastic resolution of the identity to decouple the 4-index electron repulsion integrals (ERI). To improve the time-propagation and the spectral resolution, we adopt the dynamic mode decomposition (DMD) technique and assess the accuracy and efficiency of the combined approach for a chain of hydrogen dimer molecules of different lengths. We find that the stochastic implementation accurately reproduces the deterministic results for the electronic dynamics and excitation energies. Furthermore, we provide a detailed analysis of the statistical errors, bias, and long-time extrapolation. Overall, the approach offers an efficient route to investigate excited states in extended systems with open or closed boundary conditions. |
| title | Stochastic Real-Time Second-Order Green's Function Theory for Neutral Excitations in Molecules and Nanostructures |
| topic | Chemical Physics |
| url | https://arxiv.org/abs/2303.06874 |