XXZ Bethe states as highest weight vectors of the $sl_2$ loop algebra at roots of unity

dc.creatorDeguchi, Tetsuo
dc.date2002-12-10
dc.date2003-03-22
dc.date.accessioned2026-07-07T02:48:38Z
dc.date.available2026-07-07T02:48:38Z
dc.descriptionWe prove some part of the conjecture that regular Bethe ansatz eigenvectors of the XXZ spin chain at roots of unity are highest weight vectors of the $sl_2$ loop algebra. Here $q$ is related to the XXZ anisotropic coupling $Δ$ by $Δ=(q+q^{-1})/2$, and it is given by a root of unity, $q^{2N}=1$, for a positive integer $N$. We show that regular XXZ Bethe states are annihilated by the generators ${\bar x}_k^{+}$'s, for any $N$. We discuss, for some particular cases of N=2, that regular XXZ Bethe states are eigenvectors of the generators of the Cartan subalgebra, ${\bar h}_k$'s. Here the loop algebra $U(L(sl_2))$ is generated by ${\bar x}_k^{\pm}$ and ${\bar h}_k$ for $k \in {\bf Z}$, which are the classical analogues of the Drinfeld generators of the quantum loop algebra $U_q(L(sl_2))$. A representation of $U(L(sl_2))$ is called highest weight if it is generated by a vector $Ω$ which is annihilated by the generators ${\bar x}_k^{+}$'s and such that $Ω$ is an eigenvector of the ${\bar h}_k$'s. We also discuss the classical analogue of the Drinfeld polynomial which characterizes the irreducible finite-dimensional highest weight representation of $U(L(sl_2))$.
dc.descriptionAn almost completed note, 13 pages, no figures
dc.identifierhttps://arxiv.org/abs/cond-mat/0212217
dc.identifierhttp://arxiv.org/abs/cond-mat/0212217
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/20484
dc.subjectStatistical Mechanics
dc.titleXXZ Bethe states as highest weight vectors of the $sl_2$ loop algebra at roots of unity
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