Boson correlation energies via variational minimization with the two-particle reduced density matrix: Exact N-representability conditions for harmonic interactions
- Department of Chemistry and the James Franck Institute, University of Chicago, Chicago, Illinois 60637 (United States)
A many-body theory for interacting bosons is developed within the framework of minimizing the ground-state energy with respect to the two-particle reduced-density matrix (2-RDM) subject to N-representability conditions. The N-representability conditions, which ensure that the 2-RDM may be derived from an N-particle wave function, are imposed through a hierarchy of positivity conditions where the p-positivity conditions restrict the metric matrices for p/2-body operators to be positive semidefinite. Using two-positivity, we minimize the ground-state energies of 5-10 000 harmonically interacting bosons in a harmonic external potential. The energies and 2-RDMs obtained are in agreement with the exact solution except for round-off errors, which implies that for this class of boson interactions two-positivity conditions alone yield exact results for any interaction strength. The ground-state energies obtained at strong interactions are more accurate than many-body perturbative techniques by many orders of magnitude.
- OSTI ID:
- 20640981
- Journal Information:
- Physical Review. A, Vol. 69, Issue 4; Other Information: DOI: 10.1103/PhysRevA.69.042511; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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