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arXiv · 1303.4112

Quasi-particle approach for general lattice Hamiltonians

Patrick Navez·Friedemann Queisser·Ralf Schützhold
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Abstract

In many condensed-matter systems, it is very useful to introduce a quasi-particle approach, which is based on some sort of linearization around a suitable background state. In order to be a systematic and controlled approximation, this linearization should be justified by an expansion into powers of some small control parameter. Here, we present a method for general lattice Hamiltonians with large coordination numbers Z >> 1, which is based on an expansion into powers of 1/Z. In order to demonstrate the generality of our method, we apply it to various spin systems, as well as the Bose and Fermi Hubbard model.

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Patrick Navez, Friedemann Queisser, Ralf Schützhold. 2013-03-17. Quasi-particle approach for general lattice Hamiltonians. https://arxiv.org/abs/1303.4112

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