Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 19: Frustrated Magnets - Spin Liquids - Theory

TT 19.9: Vortrag

Montag, 12. März 2018, 17:15–17:30, H 3010

Negative sign free auxiliary field algorithm for frustrated Kondo systems — •Johannes S Hofmann¹, Fakher F Assaad¹, and Tarun Grover² — ¹Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany — ²Department of Physics, University of California at San Diego, La Jolla, CA 92093, USA

The absence of negative sign problem in quantum Monte Carlo simulations of spin and fermion systems has different origins. World-line based algorithms for spins require positivity of matrix elements whereas auxiliary field approaches for fermions depend on symmetries such as particle-hole. For negative-sign-free spin and fermionic systems, we show that one can formulate a negative-sign-free auxiliary field quantum Monte Carlo algorithm that allows Kondo coupling of fermions with the spins.

In this talk we will present preliminary results on the Kondo coupling between local moments participating in a Z₂ spin liquid (based on Balents-Fisher-Girvin model) and conduction electrons on a honeycomb lattice. Our setup allows us to address the question of the relevance of the Kondo coupling at the quantum critical point corresponding to the destruction of the spin-liquid.