Speaker
Norikazu Yamada
(KEK)
Description
We propose a subvolume method to study the $\theta$ dependence of the free energy density of the four-dimensional SU($N$) Yang-Mills theory on the lattice. As an attempt, the method is first applied to SU(2) Yang-Mills theory at $T=1.2\,T_c$ to understand the systematics of the method. We then proceed to the calculation of the vacuum energy density and obtain the $\theta$ dependence, at least, to $\theta\sim\pi$. The numerical results combined with the theoretical requirements provide the evidence for the spontaneous CP violation at $\theta = \pi$, which is in accordance with the large $N$ prediction and in contrast to the CP$^1$ model in two dimensions.
Primary author
Norikazu Yamada
(KEK)
