Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 2: Focus Session: Recent Developments in Computational Many Body Physics (joint session TT/DY)

TT 2.5: Hauptvortrag

Montag, 12. März 2018, 11:45–12:15, H 0104

Quantum Monte Carlo Simulation of Coupled Fermion-Boson Systems — Manuel Weber, Fakher Assaad, and •Martin Hohenadler — Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Germany

Problems of fermions coupled to bosonic degrees of freedom can be found in a variety of contexts in condensed matter physics. The bosons may represent, for example, quantum lattice, spin, or orbital fluctuations. Numerical simulations of such problems are challenging because of the bosonic Hilbert space, the different time scales for the fermion and boson dynamics, and the absence of efficient sampling methods for the bosons. In this talk, recent advances in quantum Monte Carlo simulations are presented. By integrating out the bosons, the original problem can be reformulated in terms of fermions with a retarded interaction. The latter can be simulated efficiently by continuous-time quantum Monte Carlo methods. Especially in combination with global updates, simulations can be carried out on system sizes currently inaccessible by any other method. Applications to be presented include the problem of competing electron-phonon couplings as well as charge-density-wave transitions in one and two dimensions.