Dresden 2017 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 8: Electronic-Structure Theory: New Concepts and Developments in Density Functional Theory and Beyond - I (joint session DS, HL, MA, MM, O, TT, organized by O)
TT 8.6: Talk
Monday, March 20, 2017, 11:45–12:00, GER 38
Density matrix embedding theory for coupled fermion-boson systems — •Teresa E. Reinhard1, Uliana Mordovina1, Heiko Appel1, Joshua S. Kretchmer2, Garnet K. L. Chan2, and Angel Rubio1,3 — 1Max Planck Institut für Struktur und Dynamik der Materie, Hamburg — 2Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena — 3Nano-bio Spectroscopy Group and ETSF, Departamento de Fisica de Materiales, Universidad del Pais Vasco UPV/EHU, San Sebastian
We analyze strongly correlated fermion-boson systems by extending Density Matrix Embedding Theory (DMET) from the purely electronic case [1] to coupled fermion-boson systems. DMET is a novel embedding theory which uses the Schmidt decomposition to divide the treated system into an impurity and a bath part. We project the bath part into the part of the Fock space that contains the entanglement with the impurity region and then solve this much smaller entangled system with exact diagonalization and DMRG.
With this technique, we treat lattice systems of Hubbard-Holstein type, where fermions and bosons are coupled by a bilinear Froehlich coupling. As we choose coherent states for the bosonic basis set, it is convenient to apply our approach to electron-phonon as well as to electron-photon systems.
By using a DMRG solver for the DMET algorithm, an accurate treatment of 2 dimensional systems becomes feasible.
[1] G. Knizia, G. K.-L Chan, Phys. Rev. Lett 109, 186404, (2012)