Non-Abelian bosonization and Haldane’s conjecture
We study the long-wavelength limit of a spin S Heisenberg antiferromagnetic chain. The fermionic Lagrangian obtained corresponds to a perturbed level 2S SU(2) Wess-Zumino-Witten (WZW) model. This effective theory is then mapped into a compact U(1) boson interacting with Z<sub>2S</sub> p...
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| Autores principales: | , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
1998
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/122954 |
| Aporte de: |
| Sumario: | We study the long-wavelength limit of a spin S Heisenberg antiferromagnetic chain. The fermionic Lagrangian obtained corresponds to a perturbed level 2S SU(2) Wess-Zumino-Witten (WZW) model. This effective theory is then mapped into a compact U(1) boson interacting with Z<sub>2S</sub> parafermions. The analysis of this effective theory allows us to show that when S is an integer there is a mass gap to all excitations, whereas this gap vanishes in the half-odd-integer spin case and the SU(2)<sub>2S</sub> WZW model flows towards the SU(2)<sub>1</sub> stable fixed point. This gives a field theory treatment of the so-called Haldane’s conjecture for arbitrary values of the spin S. |
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