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Correlation functions for composite operators in the Hubbard model

Tobias Baier·Eike Bick·Christof Wetterich
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Abstract

We compute the correlation functions for antiferromagnetic and d-wave superconducting fermion bilinears in a generalized mean field type approximation for the Hubbard model. For high temperature our explicit expressions show that homogeneous field configurations are preferred for these composite bosons. Below a critical temperature we find spontaneous symmetry breaking with homogeneous expectation values of the composite fields. Our results can be used to device a nonperturbative flow equation for the exploration of the low temperature regime.

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Tobias Baier, Eike Bick, Christof Wetterich. 2001-07-18. Correlation functions for composite operators in the Hubbard model. https://arxiv.org/abs/cond-mat/0107390

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