Towards numerically accurate many-body perturbation theory: short-range correlation effects.

Area of Science:

• Condensed Matter Physics
• Quantum Chemistry

Background:

• Short-range electron correlation significantly impacts self-energy but is numerically challenging.
• Advanced methods (e.g., GW approximation) often neglect high-momentum transfers, poorly describing short-range correlation.
• This leads to inaccurate correlation energies and quasiparticle spectra in condensed-matter studies.

Purpose of the Study:

• To address the challenge of accurately incorporating short-range electron correlation in condensed-matter calculations.
• To develop an accurate extrapolation scheme for improving correlation energy and quasiparticle spectra.
• To explain the varying difficulty in obtaining accurate GW quasiparticle spectra for different compounds.

Main Methods:

• Analytical derivation for the uniform electron gas model.
• Development of an accurate extrapolation scheme based on the analytical results.
• Application to analyze the accuracy of GW and random-phase approximations.

Main Results:

• Demonstrated the numerical difficulty of handling short-range electron correlation.
• Proposed a novel extrapolation scheme to improve accuracy.
• Provided an analytical explanation for the success or failure of GW quasiparticle spectra calculations in different materials.

Conclusions:

• The proposed extrapolation scheme effectively improves the description of short-range correlation.
• Accurate GW quasiparticle spectra are achievable with this method, explaining material-dependent difficulties.
• This work offers a pathway to more reliable electronic structure calculations in condensed matter.