Institute of Science Tokyo

Abstract：

Ab initio Quantum Monte Carlo method is another universal framework to achieve electronic structure calculations to be compared with other approaches like DFT (density functional theory) or MO (molecular orbital methods). It solves the ab initio Schrodinger equation without taking one-body forms, by using numerical Monte Carlo samplings applied directly to many-body wave functions, not decomposed into orbital functions [1]. Because of less assumptions required, the method achieves more reliable ab initio evaluations especially on the electronic correlations over DFT or MO. With high parallel efficiency achieving around 99%, the method is rapidly getting more practical to be used over such problems like magnetism [2-4], surfaces[5,6], inter-molecular interactions [7-11], and other fundamental problems[12-15], those forming generally difficult challenges to  the conventional DFT and MO. Unlike DFT with the ambiguities due to the choice of exchange-correlation functionals, or MO with the complexities in the various correction schemes indispensable, the QMC realizes simpler and straightforward evaluations toward high accuracy. These advantages push the ab initio QMC method to be a promising 'killer application' running on flagship supercomputers in US for Materials Genome, with the highest efficiency to extract the power of massive parallel computations. We will provide a hands-on tutorials for an implementation of ab initio QMC, 'CASINO'[4,7-14] package.

References：

1. R. Maezono, J. Comput. Theor. Nanosci., 6, 2474 (2009).

2. K. Hongo et al., J. Chem. Phys. 121, 7144 (2004).

3. Y. Takada et al., Phys. Rev. B. 92, 155140 (2015).

4. T. Ichibha et al., Sci. Rep. 7, 2011 (2017).

5. K. Hongo et al., J. Chem. Theory Comput. 13, 5217 (2017).

6. T. Ichibha et al., arXiv:1909.05625.

7. K.S. Qin et al., in press, Chem. Phys., arxiv:1807.04168

8. K. Hongo et al., J. Chem. Theory Comput. 11, 907 (2015).

9. A.J. Misquitta et al., Phys. Rev. B 89, 045140 (2014).

10. K. Hongo et al., J. Chem. Theory Comput. 9, 1081 (2013).

11. K. Hongo et al., Int. J. Quant. Chem. 112, 1243 (2012).

12. E. Mostaani et al., Phys. Rev. B 96, 075431 (2017).

13. R. Maezono et al., Phys. Rev. Lett. 110, 216407 (2013)

14. R. Maezono et al., Phys. Rev. Lett., 98, 025701 (2007)

15. K. Nakano et al., J. Chem. Theory Comput. 15, 4044 (2019).

About the speaker:

Dr. Ryo Maezono (PhD/Applied Physics) is a Professor at Institute of Science Tokyo, working on Materials and Informatics. He got his BSc (1995) and PhD (2000) in Applied Physics at Tokyo University, majoring condensed matter theory working on the phase diagrams of magnetic oxides. He was a JSPS fellow (Tokyo University/1999-2000), working on the magnetic properties of oxides. He got a postdoctoral position at Cavendish Laboratory, Cambridge University (EPSRC fellow/2000-2002), and moved to NIMS (National Institute of Materials Science, Japan), as a tenure researcher (2001-2007). In 2007, he moved to JAIST and had organized a research group as a full Professor until 2025. From 2025, he moved to Science Tokyo as a management Professor in the division of Materials and Informatics. Since his postdoc in Cambridge, he has worked on Diffusion Monte Carlo (DMC) electronic structure calculations using massive parallel computations. He has published several DMC works using world top class huge parallel calculations, exploring cutting-edge of numerical quantum many-body problem. As an expert of DMC method, he has given several lectures on many-body problems at Osaka University, Kyushu University, Yokohama National University Kanazawa University etc., outside of JAIST. As a computer scientist, he has contributed also to the education of simulation science, which contents are published in his books (ISBN:978-4627818217, 978-4627170315, 978-9819909186, 978-4627170322). As a researcher of computational materials science, he leads several industrial collaborations with companies (Toyota-Motor/Sumitomo-Mining/Shin-Etsu Chemicals/Asahi grass Inc./Denso Inc./Morita Chemical Inc.), as well as those with experimental synthesis community in inorganic Chemistry.

邀请人：翁红明   研究员

联系人：于乐乐 yulele@iphy.ac.cn

报告地点：物理所M楼830会议室

腾讯会议：868-549-013