Schwinger模型上的拓樸率

Abstract

在這篇論文中，我們應用最佳手則對稱之新費米場作用量(optimal domain-wall fermion)，研究Schwinger模型上的拓樸率。藉由拓樸率的定義，我們可以利用整體拓樸荷(global topological charge)來決定拓樸率。同時，透過鞍點近似法(saddle point expansion)，我們也可以在一個固定的拓樸區(fixed topological sector)內，藉由拓樸密度(topological charge density)的兩點相關係數以得到拓樸率。最後我們將證明在晶格上，這兩種方法會得出相同的拓樸率。

In this thesis, we study the topological susceptibility in the Schwinger model with optimal domain-wall fermions. We obtain the topological susceptibility from counting the global topological charge. Also, using the saddle point expansion, topological susceptibility can be extracted from the 2-point correlation functions of topological charge density in a fixed topological sector.We can demonstrate that the values obtained from this two methods are in good agreement.