Expansion algorithm for the density matrix

Preprint

21 September 2002

preprint
Published by arXiv in arXiv

https://doi.org/10.48550/arXiv.cond-mat/0209502

Abstract

A purification algorithm for expanding the single-particle density matrix in terms of the Hamiltonian operator is proposed. The scheme works with a predefined occupation and requires less than half the number of matrix-matrix multiplications compared to existing methods at low (90%) occupancy. The expansion can be used with a fixed chemical potential in which case it is an asymmetric generalization of and a substantial improvement over grand canonical McWeeny purification. It is shown that the computational complexity, measured as number of matrix multiplications, essentially is independent of system size even for metallic materials with a vanishing band gap.

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All Related Versions

Version 1, 2002-09-21, ArXiv
Published version: Physical Review B, 66 (15), 155115.

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