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arXiv 1606.08780cond-mat.str-el
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评“反铁磁自旋1链中的挫折和多临界性”

Comment on "Frustration and Multicriticality in the Antiferromagnetic Spin-1 Chain"

Natalia Chepiga, Ian Affleck, Frederic Mila

摘要:

最近由Pixley、Shashi和Nevidomskyy [Phys.Rev.B90,214426(2014)]研究的具有双线性-双二次和次近邻相互作用的自旋-1链的相图已经根据我们最近在类似模型上获得的结果重新审视。结合广泛的密度矩阵重整化群(DMRG)模拟与共形场论的论点,我们确认了Pixley等人确定的三个相的存在,Half-Phase,次近邻(NNN)Half-Phase和二聚相,但我们得出了关于二聚相的相变性质的明显不同的结论:i)我们提供了在NNN-Half相和二聚相之间连续伊辛转变的数值证据; ii)我们证明了三临界终点,在那里,Halfenic相和二聚相之间的连续转变变成一级转变,最后,我们证明了三临界终点与终止于此点的连续跃迁线处于相同的Wess-Zumino-Witten(WZW)SU(2)2级普适类中

英文摘要:

The phase diagram of the spin-1 chain with bilinear-biquadratic and next-nearest neighbor inter- actions, recently investigated by Pixley, Shashi and Nevidomskyy [Phys. Rev. B 90, 214426 (2014)], has been revisited in the light of results we have recently obtained on a similar model. Combining extensive Density Matrix Renormalization Group (DMRG) simulations with conformal-field theory arguments, we confirm the presence of the three phases identified by Pixley et al, a Haldane phase, a next-nearest neighbor (NNN) Haldane phase, and a dimerized phase, but we come to significantly different conclusions regarding the nature of the phase transitions to the dimerized phase: i) We provide numerical evidence of a continuous Ising transition between the NNN-Haldane phase and the dimerized phase; ii) We show that the tri-critical end point, where the continuous transition between the Haldane phase and the dimerized phase turns into a first order transition, is distinct from the triple point where the three phases meet; iii) Finally, we demonstrate that the tri-critical end point is in the same Wess-Zumino-Witten (WZW) SU(2) level 2 universality class as the continuous transition line that ends at this point

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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