Variational reduced density matrix method in the doubly-occupied configuration interaction space using four-particle N-representability conditions: Application to the XXZ model of quantum magnetism
Year: 2019
Type: article
Abstract: This work deals with the variational determination of the two-particle reduced density matrix (2-RDM) and the energy corresponding to the ground state of N-particle systems within the doubly occupied configuration interaction (DOCI) space. Here, we impose for the first time up to four-particle N-representability constraint conditions in the variational determination of the 2-RDM matrix elements using the standard semidefinite programming algorithms. The energies and 2-RDMs obtained from this treatment and the corresponding computational costs are compared with those arisen from previously reported less restrictive variational methods [D. R. Alcoba et al., J. Chem. Phys. 149, 194105 (2018)] as well as with the exact DOCI values. We apply the different approximations to the one-dimensional XXZ model of quantum magnetism, which has a rich phase diagram with one critical phase and constitutes a stringent test for the method. The numerical results show the usefulness of our treatment to achieve a high degree of accuracy.
Source: The Journal of Chemical Physics
DOI: 10.1063/1.5118899
Institutions: Instituto de Estructura de la Materia, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Física de Buenos Aires, Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Universidad Nacional de La Plata, University of the Basque Country
Language: English
Topic: Quantum many-body systems
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: Ministerio de Ciencia, Innovación y Universidades, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Agencia Nacional de Promoción Científica y Tecnológica, European Regional Development Fund, Secretaría de Ciencia y Técnica, Universidad de Buenos Aires
Awards: G1353864285, G2403323098, ESTUDIO Y DESARROLLO DE MODELOS EN LA TEORÍA QSAR/QSPR PARA LA PREDICCIÓN DE PROPIEDADES FISICOQUÍMICAS Y BIOLÓGICAS EN SISTEMAS MOLECULARES Y MACROMOLECULARES, G3779443375, G3863562413, G4521559834, G5176764596, G5975792943, G6019714971, G6728930308, G6731467812, G687022500, G7738492125, Átomos ultra fríos atrapados en pozos múltiples, G8232009390, G8450008009, G8594361670, Ecuaciones de Schrödinger y Liouville-von Neumann Contraídas: Determinación Directa de Matrices de Densidad Reducida de 2-electrones en Sistemas Atómicos y Moleculares, G869346897
OpenAlex ID: W2980454012