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 U/t=4 and U/t=1, for ω0/t=1, indicate a region around U≃g2ω0 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.

Solution of the sign problem for the half-filled Hubbard-Holstein model / Karakuzu, Seher; Seki, Kazuhiro; Sorella, Sandro. - In: PHYSICAL REVIEW. B. - ISSN 2469-9950. - 98:20(2018), pp. 1-5. [10.1103/PhysRevB.98.201108]

Solution of the sign problem for the half-filled Hubbard-Holstein model

Karakuzu, Seher
Membro del Collaboration group
;
Seki, Kazuhiro
Membro del Collaboration group
;
Sorella, Sandro
Membro del Collaboration group
2018-01-01

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 U/t=4 and U/t=1, for ω0/t=1, indicate a region around U≃g2ω0 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.
2018
98
20
1
5
201108
http://harvest.aps.org/bagit/articles/10.1103/PhysRevB.98.201108/apsxml
https://arxiv.org/abs/1808.07759
Karakuzu, Seher; Seki, Kazuhiro; Sorella, Sandro
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/87967
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