arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1402.4081cond-mat.str-el
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弦网模型的推广和局限性

Generalizations and limitations of string-net models

Chien-Hung Lin, Michael Levin

摘要:

我们问拓扑相位可以和不能实现的完全可溶性弦网络模型。我们回答这个问题的最简单的一类拓扑阶段,即那些阿贝尔编织统计。具体地说,我们发现一个阿贝尔拓扑相可以实现的弦网络模型,当且仅当(i)它有一个消失的热霍尔电导和(ii)它有至少一个拉格朗日子群--一个子集的准粒子具有特定的拓扑性质。等价地,我们发现一个阿贝尔拓扑相是可实现的当且仅当它支持一个间隙边。我们猜想,后者的标准推广到非阿贝尔的情况下。我们通过系统地构造所有可能的阿贝尔弦网模型并分析每个模型中的准粒子编织统计来建立这些结果。我们证明了这些模型的低能有效场论是多分量U(1)Chern-Simons理论,并导出了每个模型的K矩阵描述。这项工作的另一个特点是,由于几个新的成分,我们构建的模型比原来的弦网模型更一般。首先,我们引入了两个新的对象$γ, α$到构造中,它们与$\mathbb{Z}_2$和$\mathbb{Z}_3$ Frobenius-Schur指标相关。第二,我们不假设宇称不变性。因此,我们可以实现原始构造无法访问的拓扑相位,包括打破时间反演和宇称对称的相位。

英文摘要:

We ask which topological phases can and cannot be realized by exactly soluble string-net models. We answer this question for the simplest class of topological phases, namely those with abelian braiding statistics. Specifically, we find that an abelian topological phase can be realized by a string-net model if and only if (i) it has a vanishing thermal Hall conductance and (ii) it has at least one Lagrangian subgroup --- a subset of quasiparticles with particular topological properties. Equivalently, we find that an abelian topological phase is realizable if and only if it supports a gapped edge. We conjecture that the latter criterion generalizes to the non-abelian case. We establish these results by systematically constructing all possible abelian string-net models and analyzing the quasiparticle braiding statistics in each model. We show that the low energy effective field theories for these models are multicomponent U(1) Chern-Simons theories, and we derive the K-matrix description of each model. An additional feature of this work is that the models we construct are more general than the original string-net models, due to several new ingredients. First, we introduce two new objects $γ, α$ into the construction which are related to $\mathbb{Z}_2$ and $\mathbb{Z}_3$ Frobenius-Schur indicators. Second, we do not assume parity invariance. As a result, we can realize topological phases that were not accessible to the original construction, including phases that break time-reversal and parity symmetry.

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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