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arXiv · 1207.2314

Renormalization group flow for fermions into antiferromagnetically ordered phases: Method and mean-field models

Stefan A. Maier·Carsten Honerkamp
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Abstract

We present a functional renormalization group flow for many-fermion lattice models into phases with broken spin-rotational symmetry. The flow is expressed purely in terms of fermionic vertex functions. The symmetry breaking is seeded by a small initial anomalous self-energy which grows at the transition scale and which prevents a runaway-flow at nonzero scales. Focusing on the case of commensurate antiferromagnetism we discuss how the interaction vertex can be parametrized efficiently. For reduced models with long-range bare interactions we show the results of standard mean-field theory are reproduced by the fRG and how anisotropies in the spin sector change the flows. We then describe a more efficient decomposition of the interaction vertex that should allow for the treatment of more general models.

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Stefan A. Maier, Carsten Honerkamp. 2012-07-10. Renormalization group flow for fermions into antiferromagnetically ordered phases: Method and mean-field models. https://doi.org/10.1103/physrevb.86.134404

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