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Regularized second-order correlation methods for extended systems.
Elisabeth Keller1, Theodoros Tsatsoulis1, Karsten Reuter1
1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
Regularization techniques improve the accuracy of second-order Møller-Plesset perturbation theory (MP2) for challenging condensed matter systems. These methods address limitations in metallic, polarizable, and strongly correlated materials.
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Area of Science:
- Computational chemistry
- Condensed matter physics
- Quantum mechanics
Background:
- Second-order Møller-Plesset perturbation theory (MP2) is a widely used method for electronic structure calculations.
- MP2 offers a balance between computational cost and accuracy but has known limitations.
- MP2 fails for certain systems, such as the homogeneous electron gas (HEG), and overestimates dispersion interactions.
Purpose of the Study:
- To investigate regularization methods for improving MP2 performance.
- To address MP2's shortcomings in metallic, polarizable, and strongly correlated periodic systems.
- To introduce and evaluate a new size-extensive Brillouin-Wigner approach.
Main Methods:
- Application of two regularized second-order methods.
- Testing on the homogeneous electron gas (HEG).
- Analysis of the one-dimensional Hubbard model and graphene-water interactions.
Main Results:
- Regularization consistently improved results compared to standard MP2.
- Different regularizers showed varying effectiveness across different systems.
- The new Brillouin-Wigner approach demonstrated size-extensivity.
Conclusions:
- Regularization is a viable strategy to enhance MP2 accuracy for complex systems.
- Tailoring regularization techniques to specific material properties is crucial.
- The developed methods offer improved descriptions of condensed matter phenomena.

