Nonperturbative effective-field theory for two-leg antiferromagnetic spin ladders
We study the long wavelength limit of a spin-½ Heisenberg antiferromagnetic two-leg ladder, treating the interchain coupling in a nonperturbative way. We perform a mean field analysis and then include the fluctuations in an exact way. This allows for a discussion of the phase diagram of the system and...
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| Autores principales: | , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
2001
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/104431 http://hdl.handle.net/11336/98120 https://journals.aps.org/prb/abstract/10.1103/PhysRevB.63.144408 |
| Aporte de: |
| Sumario: | We study the long wavelength limit of a spin-½ Heisenberg antiferromagnetic two-leg ladder, treating the interchain coupling in a nonperturbative way. We perform a mean field analysis and then include the fluctuations in an exact way. This allows for a discussion of the phase diagram of the system and provides an effective-field theory for the low-energy excitations. The coset fermionic Lagrangian obtained corresponds toa perturbed SU(4)<sub>1</sub> / U(1) conformal field theory (CFT). This effective theory is naturally embedded in a SU(2)<sub>2</sub> x Z<sub>2</sub> CFT, where perturbations are easily identified in terms of conformal operators in the two sectors. Crossed and zigzag ladders are also discussed using the same approach. |
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