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arXiv 0709.0271cond-mat.str-elcond-mat.other
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化学势-p为负、耦合U为正的一维哈伯德模型、量子临界现象和纠缠熵

Quantum Critical Phenomena, Entanglement Entropy and Hubbard Model in 1d with the Boundary Site with a Negative Chemical Potential -p and the Hubbard Coupling U Positive

O. Hudak

摘要:

最近,我们讨论了一维哈伯德模型的半满情况下,具有L位的开链的基态和某些激发态。作者考虑了当边界点具有负化学势-p和Hubbard耦合U为正值时的情况。他们通过分析方法证明,当p大于转移积分时,Bethe ansatz方程的某些基态解变得复值。他们发现在某一临界值p_c处存在表面相变,当p < p_c时,所有的电荷激发都有能隙,而当p > p_c时,存在无质量电荷模式。为了确定这种表面相变是一级相变还是二级相变,我们使用了纠缠熵的概念。熵和它的导数在那里有一个不连续性,所以这个跃迁是一阶的。

英文摘要:

Recently the ground state and some excited states of the half-filled case of the 1d Hubbard model were discussed for an open chain with L sites. Authors considered the case when the boundary site has a negative chemical potential -p and the Hubbard coupling U is positive. They have shown by an analytic method that when p is larger than the transfer integral some of the ground-state solutions of the Bethe ansatz equations become complex-valued. They have found that there is a surface phase transition at some critical value p_c; when p < p_c all the charge excitations have the gap for this case, while there exists a massless charge mode when p > p_c. To find whether this surface phase transition is of the first order or of the second order we have used the entanglement entropy concept. The entropy and its derivative has a discontinuity there, so this transition is of the first order.

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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