2025-06-12 パシフィック・ノースウェスト国立研究所（PNNL）
本研究は、GF法の精度向上に挑み、特にTD-CCとの融合に成功して、量子多体系の高精度計算が得意な手法へと拡張しています。これは将来的に、複雑な電子・励起状態解析や新材料の理論設計に大きなインパクトをもたらす可能性があります。
＜関連情報＞
- https://www.pnnl.gov/publications/more-accurate-greens-function-simulations
- https://pubs.aip.org/aip/jcp/article/161/20/204102/3321697/Exploring-the-exact-limits-of-the-real-time
実時間運動方程式結合クラスター キュムラント グリーン関数の正確な限界を探る
Exploring the exact limits of the real-time equation-of-motion coupled cluster cumulant Green’s functions
Bo Peng;Himadri Pathak;Ajay Panyala;Fernando D. Vila;John J. Rehr;Karol Kowalski
The Journal of Chemical Physics Published:November 22 2024
DOI:https://doi.org/10.1063/5.0233339
In this paper, we analyze the properties of the recently proposed real-time equation-of-motion coupled-cluster (RT-EOM-CC) cumulant Green’s function approach [Rehr et al., J. Chem. Phys. 152, 174113 (2020)]. We specifically focus on identifying the limitations of the original time-dependent coupled cluster (TDCC) ansatz and propose an enhanced double TDCC ansatz, ensuring the exactness in the expansion limit. In addition, we introduce a practical cluster-analysis-based approach for characterizing the peaks in the computed spectral function from the RT-EOM-CC cumulant Green’s function approach, which is particularly useful for the assignments of satellite peaks when many-body effects dominate the spectra. Our preliminary numerical tests focus on reproducing, approximating, and characterizing the exact impurity Green’s function of the three-site and four-site single impurity Anderson models using the RT-EOM-CC cumulant Green’s function approach. The numerical tests allow us to have a direct comparison between the RT-EOM-CC cumulant Green’s function approach and other Green’s function approaches in the numerical exact limit.
