论文标题

具有随机噪声的张量网络的全模式重归其化

All-mode Renormalization for Tensor Network with Stochastic Noise

论文作者

Arai, Erika, Ohki, Hiroshi, Takeda, Shinji, Tomii, Masaaki

论文摘要

在通常的(非传统)张量网络计算中,截断的奇异值分解(SVD)通常用于近似张量,并导致系统错误。但是,通过在近似值中引入随机噪声,可以避免以统计误差为代价来避免这种系统误差,而统计误差可以直接控制。因此,原则上,即使在有限债券维度达到统计误差,也可以获得精确的结果。然而,先前对张量重量规定组(TRG)算法实现的无偏方法的研究表明,物理量的统计误差不可忽略,而且计算成本与系统量成正比。在本文中,我们引入了一种新的随机噪声方式,以便抑制统计误差,此外,为了降低计算成本,我们提出的常见噪声方法的成本与数量的对数成正比。我们发现,与截短的SVD相比,该方法可为自由能提供更好的精度,以在TRG上用于Square Grattice上的ISING模型。尽管通用噪声方法引入了系统误差源于声音的相关性,但我们表明该误差可以用简单的函数形式描述,以噪音的数量来描述,因此可以在实际分析中直接控制误差。我们还将方法应用于独立的局部截断算法,并表明准确性得到了进一步提高。

In usual (non-stochastic) tensor network calculations, the truncated singular value decomposition (SVD) is often used for approximating a tensor, and it causes systematic errors. By introducing stochastic noise in the approximation, however, one can avoid such systematic errors at the expense of statistical errors which can be straightforwardly controlled. Therefore in principle, exact results can be obtained even at finite bond dimension up to the statistical errors. A previous study of the unbiased method implemented in tensor renormalization group (TRG) algorithm, however, showed that the statistical errors for physical quantity are not negligible, and furthermore the computational cost is linearly proportional to a system volume. In this paper, we introduce a new way of stochastic noise such that the statistical error is suppressed, and moreover, in order to reduce the computational cost we propose common noise method whose cost is proportional to the logarithm of volume. We find that the method provides better accuracy for the free energy compared with the truncated SVD when applying to TRG for Ising model on square lattice. Although the common noise method introduces systematic error originated from a correlation of noises, we show that the error can be described by a simple functional form in terms of the number of noises, thus the error can be straightforwardly controlled in an actual analysis. We also apply the method to the graph independent local truncation algorithm and show that the accuracy is further improved.

扫码加入交流群

加入微信交流群

微信交流群二维码

扫码加入学术交流群,获取更多资源