### Abstract

For the first order density matrix P of a noninteracting N-electron problem, an iterative formula is presented that preserves the trace and idempotency of P so that no purification is needed. Hermiticity-which may be slightly violated in the course of the iteration-gets restored when the iteration converges and the converged P corresponds to the exact solution. For sparse P, the energy is obtained by an O(N) procedure that needs no prior knowledge of the chemical potential. Illustrative calculations in tight-binding and abinitio Hartree-Fock levels are presented.

Original language | English |
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Article number | 013002 |

Journal | Physical Review Letters |

Volume | 95 |

Issue number | 1 |

DOIs | |

Publication status | Published - júl. 1 2005 |

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### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

**Idempotency-conserving iteration scheme for the one-electron density matrix.** / Kohalmi, Dóra; Szabados, A.; Surján, P.

Research output: Article

*Physical Review Letters*, vol. 95, no. 1, 013002. https://doi.org/10.1103/PhysRevLett.95.013002

}

TY - JOUR

T1 - Idempotency-conserving iteration scheme for the one-electron density matrix

AU - Kohalmi, Dóra

AU - Szabados, A.

AU - Surján, P.

PY - 2005/7/1

Y1 - 2005/7/1

N2 - For the first order density matrix P of a noninteracting N-electron problem, an iterative formula is presented that preserves the trace and idempotency of P so that no purification is needed. Hermiticity-which may be slightly violated in the course of the iteration-gets restored when the iteration converges and the converged P corresponds to the exact solution. For sparse P, the energy is obtained by an O(N) procedure that needs no prior knowledge of the chemical potential. Illustrative calculations in tight-binding and abinitio Hartree-Fock levels are presented.

AB - For the first order density matrix P of a noninteracting N-electron problem, an iterative formula is presented that preserves the trace and idempotency of P so that no purification is needed. Hermiticity-which may be slightly violated in the course of the iteration-gets restored when the iteration converges and the converged P corresponds to the exact solution. For sparse P, the energy is obtained by an O(N) procedure that needs no prior knowledge of the chemical potential. Illustrative calculations in tight-binding and abinitio Hartree-Fock levels are presented.

UR - http://www.scopus.com/inward/record.url?scp=27144519896&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=27144519896&partnerID=8YFLogxK

U2 - 10.1103/PhysRevLett.95.013002

DO - 10.1103/PhysRevLett.95.013002

M3 - Article

VL - 95

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 1

M1 - 013002

ER -