Quantum Monte Carlo for strongly correlated electronic systemsSupervisor: Ing. Matúš Dubecký, PhD.
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|Project description:||In recent years, single-determinant fixed-node diffusion Monte Carlo (FNDMC) reached high-standard accuracy in a number of diverse systems (where mean-field methods like DFT do not suffice) ranging from weakly bound noncovalent complexes to strongly correlated systems like solid transition-metal oxides at high pressures. Thanks to its favourable CPU cost scaling, parallelism, and direct access to periodicity, FNDMC gains popularity as an unprecedented benchmark tool for large realistic complex many-electron systems. Recent results however suggest, that the expected accuracy is not always accessible, sometimes the results are overvalued, or they depend on the parameters that have been ignored to date. The reason being incomplete understanding of FN approximation (FNA) and its interplay with other possible biases. Our goal is identification and development of deep conceptual understanding of the key FNDMC error sources in strong interaction limit. We plan to uncover the currently unknown links between generic nodal (position-space) properties (e.g.,topology) of fermionic wave functions, and, their connection to the structure of many-determinant expansions and 1-particle reduced density matrix occupation numbers, as well as separation of electron correlation energy to dynamic and nondynamic (strong, multireference) component, which will enable fundamental understanding of FNA limits and decoupling of FN-bias from other bias sources of FNDMC. We also plan screening of FNDMC accuracy in strongly interacting model systems and unprecedented method developments that go beyond FN approximation. In addition to deep physical insights to the strong correlation effects in complex many-electron systems and limits of FNDMC methodology, the results of the project will enable rational usage and fine bias control of this method valuable for large systems.|
|Kind of project:||APVV - Všeobecná výzva ()|
|Department:||Advanced Technologies Research Institute (MTF)|
|Project status:||In process of execution|
|Project start date :||01. 07. 2019|
|Project close date:||30. 06. 2023|
|Number of workers in the project:||4|
|Number of official workers in the project:||4|
The following table shows the researcher workers who have been assigned official roles in a project.
|Ing. Matúš Dubecký, PhD.||zodpovedný riešiteľ|
|Mgr. Ingrida Bajčičáková, PhD.||spoluriešiteľ|
|RNDr. Ing. Vladimír Kolesár, PhD.||spoluriešiteľ|
|doc. Ing. Stanislav Minárik, PhD.||spoluriešiteľ|