Accelerating Core-Level GW Calculations by Combining the Contour Deformation Approach with the Analytic Continuation...

Area of Science:

• Computational physics and chemistry
• Quantum mechanical methods
• Materials science

Background:

• The GW method is crucial for accurate core-level binding energy calculations.
• Contour deformation (CD) offers an efficient approach for GW self-energy in deep core excitations.
• Current CD methods face high computational scaling (O(N^5)) for core-level calculations.

Purpose of the Study:

• To develop a more computationally efficient GW method for core-level binding energies.
• To reduce the scaling of the contour deformation (CD) technique for core-level calculations.
• To maintain the numerical accuracy of CD for deep core excitations.

Main Methods:

• Introduction of the CD-WAC (CD with W analytic continuation) method.
• Analytic continuation (AC) of the screened Coulomb interaction (W) to reduce scaling.
• Implementation and testing on benchmark datasets (e.g., CORE65) and large systems (acene chains, amorphous carbon).

Main Results:

• Reduced computational scaling of CD for core-level GW calculations from O(N^5) to O(N^4).
• High numerical accuracy maintained, with mean absolute errors <5 meV for single-shot GW calculations.
• Achieved speedups of up to 10x on large systems, confirming theoretical scaling.

Conclusions:

• The CD-WAC method significantly improves the computational efficiency of core-level GW calculations.
• This advancement enables accurate and efficient studies of larger and more complex systems.
• CD-WAC is a reliable and scalable method for deep core-level GW computations.