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Related Experiment Video

Updated: Mar 27, 2026

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Published on: June 8, 2018

Canonical density matrix perturbation theory.

Anders M N Niklasson¹, M J Cawkwell¹, Emanuel H Rubensson²

¹Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.

Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics

|January 15, 2016

Summary

This summary is machine-generated.

Density matrix perturbation theory is extended to canonical ensembles for calculating temperature-dependent properties. This method offers linear scaling computational cost for large systems using sparse matrix algebra.

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Published on: May 27, 2020

Area of Science:

Computational physics and chemistry
Materials science

Background:

Density matrix perturbation theory provides a framework for calculating material properties.
Extending these methods to canonical ensembles is crucial for understanding temperature-dependent behavior.

Purpose of the Study:

Generalize density matrix perturbation theory to canonical (NVT) free-energy ensembles.
Enable calculation of temperature-dependent response properties.

Main Methods:

Extension of canonical density matrix perturbation theory.
Utilizing coupled perturbed self-consistent field equations.
Application within tight-binding, Hartree-Fock, and Kohn-Sham density-functional theory.

Main Results:

Successful generalization of density matrix perturbation theory to NVT ensembles.
Demonstrated capability to compute temperature-dependent response properties.
Achieved linear scaling computational cost for large nonmetallic materials and metals at high temperatures through sparse matrix algebra.

Conclusions:

The generalized theory provides an efficient route to temperature-dependent properties.
The method's linear scaling complexity is advantageous for large-scale simulations.
This approach enhances the study of materials under varying thermal conditions.