The sl_2 loop algebra symmetry of the six-vertex model at roots of unity

Tetsuo Deguchi; Klaus Fabricius; Barry M. McCoy

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The sl_2 loop algebra symmetry of the six-vertex model at roots of unity

Tetsuo Deguchi·Klaus Fabricius·Barry M. McCoy

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Abstract

We demonstrate that the six vertex model (XXZ spin chain) with $Δ=(q+q^{-1})/2$ and $q^{2N}=1$ has an invariance under the loop algebra of $sl_2$ which produces a special set of degenerate eigenvalues. For $Δ=0$ we compute the multiplicity of the degeneracies using Jordan Wigner techniques

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Tetsuo Deguchi, Klaus Fabricius, Barry M. McCoy. 2000-01-18. The sl_2 loop algebra symmetry of the six-vertex model at roots of unity. https://arxiv.org/abs/cond-mat/9912141

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