Excitations and the tangent space of projected entangled-pair states
Excitations and the tangent space of projected entangled-pair states
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DOI：
10.1103/physrevb.92.201111
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发表时间：
2015-07
影响因子：
3.7
通讯作者：
L. Vanderstraeten;M. Marien;F. Verstraete;J. Haegeman
中科院分区：
文献类型：
--
作者：
L. Vanderstraeten;M. Marien;F. Verstraete;J. Haegeman
我们开发了投影纠缠对态（PEPS）的切空间方法，提供了直接访问强相关二维量子系统的低能部分的方法。更具体地说，我们在PEPS基态之上构建了一个基本激发的变分分析，允许在热力学极限下直接计算间隙、色散关系和谱权。求解相应的变分问题需要在PEPS背景下计算动量转换后的两点和三点相关函数，我们可以使用收缩格式高效地计算。作为一个应用，我们研究了方形晶格上的Affleck-Kennedy-Lieb-Tasaki模型的磁振子的谱性质以及基塔伊夫环面码的摄动版本中的任意子激发。
We develop tangent space methods for projected entangled-pair states (PEPS) that provide direct access to the low-energy sector of strongly-correlated two-dimensional quantum systems. More specifically, we construct a variational ansatz for elementary excitations on top of PEPS ground states that allows for computing gaps, dispersion relations, and spectral weights directly in the thermodynamic limit. Solving the corresponding variational problem requires the evaluation of momentum transformed two-point and three-point correlation functions on a PEPS background, which we can compute efficiently by using a contraction scheme. As an application we study the spectral properties of the magnons of the Affleck-Kennedy-Lieb-Tasaki model on the square lattice and the anyonic excitations in a perturbed version of Kitaev's toric code.