Abstract
We show that, by an appropriate choice of auxiliary fields and exact integration of the phonon degrees of freedom, it is possible to define a “sign-free” path integral for the so-called Hubbard-Holstein model at half filling. We use a statistical method, based on an accelerated and efficient Langevin dynamics, for evaluating all relevant correlation functions of the model. Preliminary calculations at and , for , indicate a region around without either antiferromagnetic or charge-density-wave orders that is much wider compared to previous approximate calculations. The elimination of the sign problem in a model without explicit particle-hole symmetry may open different perspectives for strongly correlated models, even away from the purely attractive or particle-hole symmetric cases.
- Received 24 August 2018
- Revised 26 October 2018
DOI:https://doi.org/10.1103/PhysRevB.98.201108
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