Dresden 2020 – wissenschaftliches Programm
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TT 33.8: Vortrag
Mittwoch, 18. März 2020, 11:30–11:45, HSZ 201
Novel approach to non-local correlations: dual boson diagrammatic monte carlo — •Matteo Vandelli1,2, Evgeny Stepanov1, Angel Rubio2, and Alexander Lichtenstein1 — 1Institute of Theoretical Physics, University of Hamburg, 20355 Hamburg, Germany — 2Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
A long list of interesting physical phenomena arises due to strong interactions among electrons, but the mechanisms behind them are not fully understood yet. One of the most successful methods to deal with correlations is Dynamical Mean Field Theory (DMFT). However diagrammatic extensions are needed to capture non-local correlations. In particular dual theories are very promising, since they are based on an exact transformation. Recently Gukelberger et al. [PhysRevB.96.035152] have proven that the combination of Dual Fermion approach with diagrammatic Monte Carlo (DiagMC@DF) reproduces very accurately the results based on numerically exact Monte Carlo benchmarks. We expanded this scheme so that we could include non-local interactions appearing in the Extended Hubbard model. In order to achieve this goal, we combined diagrammatic Monte Carlo with Dual Boson approach (DiagMC@DB). The main advantage of this technique is that it can capture the interplay between competing instabilities. Furthermore the algorithm samples all the possible Feynman diagrams, as opposed to other diagrammatic approaches that arbitrarily select only some topologies.