Multi-orbital two-particle self-consistent approach – Strengths and limitations
Extending many-body numerical techniques which are powerful in the context of simple model calculations to the realm of realistic material simulations can be a challenging task. Realistic systems often involve multiple active orbitals, which increases the complexity and numerical cost because of the...
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2025-07-01
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| Series: | SciPost Physics |
| Online Access: | https://scipost.org/SciPostPhys.19.1.026 |
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| author | Jonas B. Profe, Jiawei Yan, Karim Zantout, Philipp Werner, Roser Valentí |
| author_facet | Jonas B. Profe, Jiawei Yan, Karim Zantout, Philipp Werner, Roser Valentí |
| author_sort | Jonas B. Profe, Jiawei Yan, Karim Zantout, Philipp Werner, Roser Valentí |
| collection | DOAJ |
| description | Extending many-body numerical techniques which are powerful in the context of simple model calculations to the realm of realistic material simulations can be a challenging task. Realistic systems often involve multiple active orbitals, which increases the complexity and numerical cost because of the large local Hilbert space and the large number of interaction terms or sign-changing off-diagonal Green's functions. The two-particle self-consistent approach (TPSC) is one such many-body numerical technique, for which multi-orbital extensions have proven to be involved due to the substantially more complex structure of the local interaction tensor. In this paper we extend earlier multi-orbital generalizations of TPSC by setting up two different variants of a fully self-consistent theory for TPSC in multi-orbital systems. We first investigate the strengths and limitations of the approach analytically and then benchmark both variants against dynamical mean-field theory (DMFT) and D-TRILEX results. We find that the exact behavior of the system can be faithfully reproduced in the weak-coupling regime, while at stronger couplings the performance of the two TPSC variants strongly depends on details of the system. |
| format | Article |
| id | doaj-art-7f8bf012e2ca436d99b561fffdf0a45d |
| institution | DOAJ |
| issn | 2542-4653 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | SciPost |
| record_format | Article |
| series | SciPost Physics |
| spelling | doaj-art-7f8bf012e2ca436d99b561fffdf0a45d2025-08-20T02:40:32ZengSciPostSciPost Physics2542-46532025-07-0119102610.21468/SciPostPhys.19.1.026Multi-orbital two-particle self-consistent approach – Strengths and limitationsJonas B. Profe, Jiawei Yan, Karim Zantout, Philipp Werner, Roser ValentíExtending many-body numerical techniques which are powerful in the context of simple model calculations to the realm of realistic material simulations can be a challenging task. Realistic systems often involve multiple active orbitals, which increases the complexity and numerical cost because of the large local Hilbert space and the large number of interaction terms or sign-changing off-diagonal Green's functions. The two-particle self-consistent approach (TPSC) is one such many-body numerical technique, for which multi-orbital extensions have proven to be involved due to the substantially more complex structure of the local interaction tensor. In this paper we extend earlier multi-orbital generalizations of TPSC by setting up two different variants of a fully self-consistent theory for TPSC in multi-orbital systems. We first investigate the strengths and limitations of the approach analytically and then benchmark both variants against dynamical mean-field theory (DMFT) and D-TRILEX results. We find that the exact behavior of the system can be faithfully reproduced in the weak-coupling regime, while at stronger couplings the performance of the two TPSC variants strongly depends on details of the system.https://scipost.org/SciPostPhys.19.1.026 |
| spellingShingle | Jonas B. Profe, Jiawei Yan, Karim Zantout, Philipp Werner, Roser Valentí Multi-orbital two-particle self-consistent approach – Strengths and limitations SciPost Physics |
| title | Multi-orbital two-particle self-consistent approach – Strengths and limitations |
| title_full | Multi-orbital two-particle self-consistent approach – Strengths and limitations |
| title_fullStr | Multi-orbital two-particle self-consistent approach – Strengths and limitations |
| title_full_unstemmed | Multi-orbital two-particle self-consistent approach – Strengths and limitations |
| title_short | Multi-orbital two-particle self-consistent approach – Strengths and limitations |
| title_sort | multi orbital two particle self consistent approach strengths and limitations |
| url | https://scipost.org/SciPostPhys.19.1.026 |
| work_keys_str_mv | AT jonasbprofejiaweiyankarimzantoutphilippwernerroservalenti multiorbitaltwoparticleselfconsistentapproachstrengthsandlimitations |