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arXiv 1012.1753cond-mat.stat-mechhep-thmath-phmath.MP
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交错$U_q[sl(2|1)]$超自旋链的有限尺寸性质

Finite size properties of staggered $U_q[sl(2|1)]$ superspin chains

Holger Frahm, Marcio J. Martins

摘要:

基于三维基本表象和对偶表象交替建立的$U_q[sl(2|1)]$顶点模型本征值问题的精确解,利用代数Bethe变换,我们研究了相应的混合超自旋链在形变参数$q=\exp(-iγ/2)$下的基态和低能激发.该模型有一个中心电荷$c=0$和连续的共形尺寸组成的部门与$γ$依赖的下边缘$0\leγ<π/2$的临界点线。有限尺寸的标度行为是一致的低能量有效的理论组成的一个紧凑和一个非紧凑的玻色子自由度。在“铁磁”制度$π<γ\le2π$的临界理论有$c=-1$的指数连续变化的变形参数。自旋和电荷的自由度是分离的有限尺寸的频谱,这与$U_q[osp(2|2)]$自旋链的一致。在中间制度$π/2<γ<π$的基态能量的有限尺寸缩放依赖于变形参数。

英文摘要:

Based on the exact solution of the eigenvalue problem for the $U_q[sl(2|1)]$ vertex model built from alternating 3-dimensional fundamental and dual representations by means of the algebraic Bethe ansatz we investigate the ground state and low energy excitations of the corresponding mixed superspin chain for deformation parameter $q=\exp(-iγ/2)$. The model has a line of critical points with central charge $c=0$ and continua of conformal dimensions grouped into sectors with $γ$-dependent lower edges for $0\leγ<π/2$. The finite size scaling behaviour is consistent with a low energy effective theory consisting of one compact and one non-compact bosonic degree of freedom. In the 'ferromagnetic' regime $π<γ\le2π$ the critical theory has $c=-1$ with exponents varying continuously with the deformation parameter. Spin and charge degrees of freedom are separated in the finite size spectrum which coincides with that of the $U_q[osp(2|2)]$ spin chain. In the intermediate regime $π/2<γ<π$ the finite size scaling of the ground state energy depends on the deformation parameter.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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