Vertex Corrections for Positive-Definite Spectral Functions of Simple Metals.

Area of Science:

• Condensed Matter Physics
• Quantum Many-Body Theory

Background:

• Electron gas models are crucial for understanding metallic properties.
• Vertex corrections are essential for accurate spectral function calculations.

Purpose of the Study:

• To systematically investigate vertex corrections in a homogeneous electron gas.
• To explore new physical processes arising from these corrections.

Main Methods:

• Utilizing a positive-definite diagrammatic expansion for the spectral function.
• Employing efficient Monte Carlo momentum integration.

Main Results:

• Identified new processes: two-plasmon generation and one-particle decay.
• Observed reduction in bandwidth and appearance of a secondary plasmon satellite.
• Documented substantial redistribution of spectral weights.

Conclusions:

• Vertex corrections significantly alter the electron gas spectral function.
• The approach shows promise for first-principles band-structure calculations.