A perturbation method in strongly correlated fermion systems

H. Keiter, Srećko Kilić

Riccardo Rossi, Fedor Šimkovic, Gabriele La Spada +4 more

Joel Feldman, Eugene Trubowitz B

Zhandos A. Moldabekov, Tobias Dornheim, G. Gregori +3 more

Correlated many-fermion systems emerge in a broad range of phenomena in warm dense matter, plasmonics, and ultracold atoms. Quantum hydrodynamics (QHD) complements first-principles methods for many-fermion systems at larger scales. We illustrate the failure of the standard Bohm potential central to QHD for strong perturbations when the density perturbation is larger than about 10^{-3} 10 − 3 of the mean density. We then extend QHD to this regime via the many-fermion Bohm potential from first-principles. This may lead to more accurate QHD simulations beyond their common application domain in the presence of strong perturbations at scales unattainable with first-principles methods.

Andrey E. Antipov, J. P. F. LeBlanc, Emanuel Gull

The dual fermion method is a multiscale approach for solving lattice problems of interacting strongly correlated systems. In this paper, we present the opendfcode, an open-source implementation of the dual fermion method applicable to fermionic single- orbital lattice models in dimensions D = 1, 2, 3 and 4. The method is built on a dynamical mean field starting point, which neglects all local correlations, and perturbatively adds spatial correlations. Our code is distributed as an open-source package under the GNU public license version 2.

Robert William Jones, Franz Mohling, Richard L. Becker