Positivity Preserving Density Matrix Minimization at Finite Temperatures via Square Root

• URL: http://arxiv.org/abs/2103.07078v3
• Date: Wed, 6 Dec 2023 23:01:26 GMT
• Title: Positivity Preserving Density Matrix Minimization at Finite Temperatures via Square Root
• Authors: Jacob M. Leamer (1), William Dawson (2), and Denys I. Bondar (1) ((1) Department of Physics and Engineering Physics, Tulane University, (2) RIKEN Center for Computational Science)
• Abstract summary: We present a method for calculating the Fermi-Dirac density matrix for electronic structure problems at finite temperature. We consider both the grand canonical (constant chemical potential) and canonical (constant number of electrons) ensembles. We show that the number of steps required for convergence is independent of the number of atoms in the system.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We present a Wave Operator Minimization (WOM) method for calculating the Fermi-Dirac density matrix for electronic structure problems at finite temperature while preserving physicality by construction using the wave operator, i.e., the square root of the density matrix. WOM models cooling a state initially at infinite temperature down to the desired finite temperature. We consider both the grand canonical (constant chemical potential) and canonical (constant number of electrons) ensembles. Additionally, we show that the number of steps required for convergence is independent of the number of atoms in the system. We hope that the discussion and results presented in this article reinvigorates interest in density matrix minimization methods.

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