Non-perturbative effective field theory for two-leg antiferromagnetic spin ladders
Abstract
We study the long wavelength limit of a spin 1/2 Heisenberg antiferromagnetic two-leg ladder, treating the interchain coupling in a non-perturbative way. We perform a mean field analysis and then include exactly the fluctuations. 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 to a perturbed SU(4)_1/U(1) Conformal Field Theory (CFT). This effective theory is naturally embedded in a SU(2)_2 x Z_2 CFT, where perturbations are easily identified in terms of conformal operators in the two sectors. Crossed and zig-zag ladders are also discussed using the same approach.
Cite
@article{arxiv.cond-mat/0010418,
title = {Non-perturbative effective field theory for two-leg antiferromagnetic spin ladders},
author = {D. C. Cabra and A. Dobry and G. L. Rossini},
journal= {arXiv preprint arXiv:cond-mat/0010418},
year = {2009}
}
Comments
14 pages LaTeX, 5 PostScript figures included using epsfig.sty; minor corrections and a few references added