Effective projection theory in a correlated electron system.
Juyeon Yi1, Seongjin Kim, Jaegon Um
1Department of Physics, Pusan National University, Busan, Korea.
Summary
We developed effective projection theory for efficient nonperturbative Green's function calculations in correlated electron systems. This method accurately captures essential correlated features across all interaction strengths.
Area of Science:
- Condensed Matter Physics
- Quantum Many-Body Theory
Background:
- Calculating Green's functions in correlated electron systems is computationally challenging.
- Nonperturbative methods are crucial for understanding strong interaction regimes.
Purpose of the Study:
- To propose an efficient, nonperturbative method for calculating Green's functions.
- To introduce and validate the effective projection theory.
Main Methods:
- Developing effective projection theory by projecting out irrelevant operators.
- Applying the method to a mesoscopic Anderson model.
- Closing equations of motion using only relevant operators for zero-temperature Green's function calculation.
Main Results:
- The method allows for the easy calculation of zero-temperature Green's functions.
- The calculated Green's functions accurately reproduce both weak and strong interaction limits.
- Comparison with exact diagonalization confirms the accuracy for small systems.
Conclusions:
- Effective projection theory provides an efficient approach for nonperturbative Green's function calculations.
- The theory successfully captures essential correlated electron system features.
- This method is applicable across the entire regime of interactions.
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