We have designed a multiscale approach for strongly correlated systems by combining the dynamical cluster approximation (DCA) and the recently introduced dual fermion formalism. This approach employs an exact mapping from a real lattice to a DCA cluster of linear size Lc embedded in a dual fermion lattice. Short-length-scale physics is addressed by the DCA cluster calculation, while longer-length-scale physics is addressed diagrammatically using dual fermions. The bare and dressed dual fermionic Green functions scale as O(1/Lc), so perturbation theory on the dual lattice converges very quickly, e.g., the dual Fermion self-energy calculated with simple second-order perturbation theory is of order O(1/Lc3) with third-order and three-body corrections down by an additional factor of O(1/Lc). © 2011 American Physical Society.
Publication Source (Journal or Book title)
Physical Review B - Condensed Matter and Materials Physics
Yang, S., Fotso, H., Hafermann, H., Tam, K., Moreno, J., Pruschke, T., & Jarrell, M. (2011). Dual fermion dynamical cluster approach for strongly correlated systems. Physical Review B - Condensed Matter and Materials Physics, 84 (15) https://doi.org/10.1103/PhysRevB.84.155106