Comparison between GW and Wave-Function-Based Approaches: Calculating the Ionization Potential and Electron Affinity...

Area of Science:

• Condensed matter physics
• Quantum chemistry

Background:

• Accurate calculation of electronic properties is crucial for understanding materials.
• The 1D Hubbard model is a fundamental system for studying electron correlation.

Purpose of the Study:

• To compare the accuracy of the GW approximation and configuration interaction (CI) methods.
• To evaluate these methods for various 1D Hubbard chain systems.
• To provide guidance on selecting appropriate computational methodologies.

Main Methods:

• GW approximation (physics-based)
• Configuration Interaction (CI) approach (chemistry-based)
• Comparison with exact diagonalization results for metallic, impurity-doped, and molecular systems.

Main Results:

• Both GW and CI methods show reasonable accuracy for weakly correlated systems.
• The GW method demonstrates superior reliability for strongly correlated systems with minimal disorder.
• Configuration interaction (CI) requires the inclusion of double excitations for comparable accuracy in strongly correlated systems.

Conclusions:

• The choice of computational method depends on the system's correlation strength and disorder.
• GW approximation is a robust choice for strongly correlated 1D systems.
• CI methods can be accurate but necessitate careful consideration of excitation levels.