Multi-reference GW approximation for strongly correlated molecules
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arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2026
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| _version_ | 1866910139531919360 |
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| author | Wang, Yuqi Fang, Wei-Hai Li, Zhendong |
| author_facet | Wang, Yuqi Fang, Wei-Hai Li, Zhendong |
| contents | The GW approximation is a cornerstone of many-body perturbation theory for computing single-particle excitations, yet it fundamentally breaks down in strongly correlated systems where the single-reference picture fails. To overcome this long-standing limitation, we introduce the multi-reference GW (MR-GW) approximation, which incorporates strong correlation effects non-perturbatively into an interacting multi-determinantal zeroth-order reference. While the standard Dyson equation is inapplicable in this setting, we show that the GW approximation can be naturally generalized by developing a rigorous diagrammatic framework with an interacting reference. Specifically, we define the MR-GW self-energy using a diagrammatic expansion based on the generalized Dyson equation, and utilize a multi-reference random phase approximation for the screened interaction, which captures many-body processes absent in standard GW. Applications to challenging strongly correlated molecules demonstrate that MR-GW seamlessly captures both strong and weak correlations, yielding more accurate ionization potentials and recovering complex many-body satellites missed by standard $GW$. This work establishes a rigorous diagrammatic paradigm for extending ab initio Green's function methods into the strongly correlated regime. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_16013 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Multi-reference GW approximation for strongly correlated molecules Wang, Yuqi Fang, Wei-Hai Li, Zhendong Chemical Physics Strongly Correlated Electrons The GW approximation is a cornerstone of many-body perturbation theory for computing single-particle excitations, yet it fundamentally breaks down in strongly correlated systems where the single-reference picture fails. To overcome this long-standing limitation, we introduce the multi-reference GW (MR-GW) approximation, which incorporates strong correlation effects non-perturbatively into an interacting multi-determinantal zeroth-order reference. While the standard Dyson equation is inapplicable in this setting, we show that the GW approximation can be naturally generalized by developing a rigorous diagrammatic framework with an interacting reference. Specifically, we define the MR-GW self-energy using a diagrammatic expansion based on the generalized Dyson equation, and utilize a multi-reference random phase approximation for the screened interaction, which captures many-body processes absent in standard GW. Applications to challenging strongly correlated molecules demonstrate that MR-GW seamlessly captures both strong and weak correlations, yielding more accurate ionization potentials and recovering complex many-body satellites missed by standard $GW$. This work establishes a rigorous diagrammatic paradigm for extending ab initio Green's function methods into the strongly correlated regime. |
| title | Multi-reference GW approximation for strongly correlated molecules |
| topic | Chemical Physics Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2604.16013 |