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arXiv · 1407.4310

Free fermion description of a paramagnetic Mott insulator

Johan Nilsson·Matteo Bazzanella
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Abstract

A scheme is presented that enables a description of a paramagnetic Mott insulator in terms of free fermions. The main idea is to view the physical fermions as a part of a multi-band system and to allow for a correlation between the physical fermions and the auxiliary ones. Technically this is implemented through a non-linear canonical transformation, which is conveniently formulated in terms of Majorana fermions. The transformed Hamiltonian is in the next stage approximated with a free fermion theory. The approximation step is variational and provides an upper bound on the ground state energy at zero or the Free energy at finite temperature.

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Johan Nilsson, Matteo Bazzanella. 2014-07-16. Free fermion description of a paramagnetic Mott insulator. https://arxiv.org/abs/1407.4310

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