Schwinger-Keldysh semionic approach for quantum spin systems
Strongly Correlated Electrons
2009-10-31 v2
Abstract
We derive a path-integral Schwinger-Keldysh approach for quantum spin systems. This is achieved by means of a semionic representation of spins as fermions with imaginary chemical potential. The major simplifying feature in comparison with other representations (Holstein-Primakoff, Dyson-Maleev, slave bosons/fermions etc) is that the local constraint is taken into account exactly. As a result, the standard diagram technique with usual Feynman codex is constructed. We illustrate the application of this technique for the N\'eel and spin-liquid states of the AFM Heisenberg model.
Cite
@article{arxiv.cond-mat/0008060,
title = {Schwinger-Keldysh semionic approach for quantum spin systems},
author = {M. N. Kiselev and R. Oppermann},
journal= {arXiv preprint arXiv:cond-mat/0008060},
year = {2009}
}
Comments
4 pages, RevTeX, 2 EPS figures included, corrected some typos, minor corrections in the text