Self-consistent GW via conservation of spectral moments
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arXiv
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| Autores principales: | , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866916884624965632 |
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| author | Backhouse, Oliver J. Allen, Marcus K. Scott, Charles C. J. Booth, George H. |
| author_facet | Backhouse, Oliver J. Allen, Marcus K. Scott, Charles C. J. Booth, George H. |
| contents | We expand on a recently introduced alternate framework for $GW$ simulation of charged excitations [Scott et. al., J. Chem. Phys., 158, 124102 (2023)], based around the conservation of directly computed spectral moments of the GW self-energy. Featuring a number of desirable formal properties over other implementations, we also detail efficiency improvements and a parallelism strategy, resulting in an implementation with a demonstrable similar scaling to an established Hartree--Fock code, with only an order of magnitude increase in cost. We also detail the applicability of a range of self-consistent $GW$ variants within this framework, including a scheme for full self-consistency of all dynamical variables, whilst avoiding the Matsubara axis or analytic continuation, allowing formal convergence at zero temperature. By investigating a range of self-consistency protocols over the GW100 molecular test set, we find that a little-explored self-consistent variant based around a simpler coupled chemical potential and Fock matrix optimization to be the most accurate self-consistent $GW$ approach. Additionally, we validate recently observed evidence that Tamm--Dancoff based screening approximations within $GW$ lead to higher accuracy than traditional random phase approximation screening over these molecular test cases. Finally, we consider the Chlorophyll A molecule, finding agreement with experiment within the experimental uncertainty, and a description of the full-frequency spectrum of charged excitations. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_17439 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Self-consistent GW via conservation of spectral moments Backhouse, Oliver J. Allen, Marcus K. Scott, Charles C. J. Booth, George H. Chemical Physics Strongly Correlated Electrons Computational Physics Quantum Physics We expand on a recently introduced alternate framework for $GW$ simulation of charged excitations [Scott et. al., J. Chem. Phys., 158, 124102 (2023)], based around the conservation of directly computed spectral moments of the GW self-energy. Featuring a number of desirable formal properties over other implementations, we also detail efficiency improvements and a parallelism strategy, resulting in an implementation with a demonstrable similar scaling to an established Hartree--Fock code, with only an order of magnitude increase in cost. We also detail the applicability of a range of self-consistent $GW$ variants within this framework, including a scheme for full self-consistency of all dynamical variables, whilst avoiding the Matsubara axis or analytic continuation, allowing formal convergence at zero temperature. By investigating a range of self-consistency protocols over the GW100 molecular test set, we find that a little-explored self-consistent variant based around a simpler coupled chemical potential and Fock matrix optimization to be the most accurate self-consistent $GW$ approach. Additionally, we validate recently observed evidence that Tamm--Dancoff based screening approximations within $GW$ lead to higher accuracy than traditional random phase approximation screening over these molecular test cases. Finally, we consider the Chlorophyll A molecule, finding agreement with experiment within the experimental uncertainty, and a description of the full-frequency spectrum of charged excitations. |
| title | Self-consistent GW via conservation of spectral moments |
| topic | Chemical Physics Strongly Correlated Electrons Computational Physics Quantum Physics |
| url | https://arxiv.org/abs/2504.17439 |