论文标题

重态度,小波和Dirichlet-Shannon内核

Renormalisation, wavelets and the Dirichlet-Shannon kernels

论文作者

Thiemann, T.

论文摘要

在建设性的量子场理论(CQFT)中,习惯首先将理论定于有限的UV和IR截止值。然后,首先,使用将有限紫外线分辨率标记的CQFT家族的重量法化技术除去紫外线截止,然后采取热力学极限。另外,人们可能会尝试直接工作而无需临界。 最近,已经提出了小波来定义CQFT的重量法流动,这是自然的,因为它们伴随着多分辨率分析(MRA)。但是,到目前为止,在非紧缩情况下大部分研究了小波。实际上,可以使用傅立叶空间技术在实际线路上构建表现紧凑的支撑和一定程度的平滑度的实际有用的小波,但是很少有明确的公式作为位置功能。可以通过在周期转换正交性属性的情况下将紧凑的支持小波进行定期,但仍会屈服于相当复杂的表达式,从而通常会失去其平稳性和位置位置属性。 它使得需要在紧凑型情况下进行小波的直接方法是可取的。在这项贡献中,我们表明,迪利奇 - 香农内核是自然缩放函数,可分别在Tori或真实线的副本上定义通用的正顺式小波碱基。这些广义小波是平滑的,是简单的明确计算功能,显示靠近HAAR小波的准本地属性,并具有紧凑的动量建议。因此,它们在位置和动力上都具有内置的截止,使其对于重态化应用非常有用。

In constructive quantum field theory (CQFT) it is customary to first regularise the theory at finite UV and IR cut-off. Then one first removes the UV cutoff using renormalisation techniques applied to families of CQFT's labelled by finite UV resolutions and then takes the thermodynamic limit. Alternatively, one may try to work directly without IR cut-off. More recently, wavelets have been proposed to define the renormalisation flow of CQFT's which is natural as they come accompanied with a multi-resolution analysis (MRA). However, wavelets so far have been mostly studied in the non-compact case. Practically useful wavelets that display compact support and some degree of smoothness can be constructed on the real line using Fourier space techniques but explicit formulae as functions of position are rarely available. Compactly supported wavelets can be periodised by summing over period translates keeping orthogonality properties but still yield to rather complicated expressions which generically lose their smoothness and position locality properties. It transpires that a direct approach to wavelets in the compact case is desirable. In this contribution we show that the Dirichlet-Shannon kernels serve as a natural scaling function to define generalised orthonormal wavelet bases on tori or copies of real lines respectively. These generalised wavelets are smooth, are simple explicitly computable functions, display quasi-local properties close to the Haar wavelet and have compact momentum supprt. Accordingly they have a built-in cut-off both in position and momentum, making them very useful for renormalisation applications.

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