A. Östlin, L. Chioncel, L. Vitos
The analytic continuation of spectral functions is an important procedure to perform in several implementations of density functional theory (DFT) where many-body effects have been added through dynamical mean field theory (DMFT). Analytic continuation is numerically ill-posed, making this a non-trivial problem to solve. Here we investigate one of the most popular analytic continuation techniques, namely the Pad\'e approximant. Aspects concerning its implementation are investigated with special regard towards making it stable and free of artificial defects. To this end electronic structure calculations are done using a single-channel scattering model, and the resulting DFT-level Green's functions are used to probe the properties of the Pad\'e approximant. It is found that the analytic properties of the approximant can be controlled by appropriate modifications, making it a robust and reliable tool for electronic structure calculations.
View original:
http://arxiv.org/abs/1209.5283
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