Reduced density matrices of Richardson-Gaudin states in the Gaudin algebra basis
| Autor: | Paul A. Johnson, Charles-Émile Fecteau, Hubert Fortin, Samuel Cloutier |
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| Rok vydání: | 2020 |
| Předmět: |
Physics
010304 chemical physics General Physics and Astronomy Electron 010402 general chemistry 01 natural sciences Quantum chemistry 0104 chemical sciences symbols.namesake 0103 physical sciences symbols Physical and Theoretical Chemistry Hamiltonian (quantum mechanics) Wave function Linear equation Eigenvalues and eigenvectors Mathematical physics Ansatz |
| Zdroj: | The Journal of chemical physics. 153(16) |
| ISSN: | 1089-7690 |
| Popis: | Eigenvectors of the reduced Bardeen-Cooper-Schrieffer Hamiltonian have recently been employed as a variational wavefunction ansatz in quantum chemistry. This wavefunction is a mean-field of pairs of electrons (geminals). In this contribution, we report optimal expressions for their reduced density matrices in both the original physical basis and the basis of the Richardson-Gaudin pairs. Physical basis expressions were originally reported by Gorohovsky and Bettelheim [Phys. Rev. B 84, 224503 (2011)]. In each case, the expressions scale like O(N4), with the most expensive step being the solution of linear equations. Analytic gradients are also reported in the physical basis. These expressions are an important step toward practical mean-field methods to treat strongly correlated electrons. |
| Databáze: | OpenAIRE |
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