Peeking into the θ vacuum

2021/02/17 by Ryuichiro Kitano, Ryutaro Matsudo, Norikazu Yamada +1 · 1 voice
Physics and Astronomy · #hep-lat #hep-ph #hep-th

paper · pdf · doi:10.1016/j.physletb.2021.136657

published as Phys.Lett.B 822 (2021) 136657 · 6 pages, 8 figures, text clarified, references added, systematic errors estimated, argument on surface tension omitted, Fig.7 added to clarify the limitation of the method, no significant change in conclusion. published version

arxiv published 2021/02/17 · arxiv created 2021/10/06 · arxiv updated 2021/10/07

Abstract

We propose a subvolume method to study the θ 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 θ dependence qualitatively different from the high temperature case. The numerical results combined with the theoretical requirements provide the evidence for the spontaneous CP violation at θ= π, which is in accordance with the large N prediction and indicates that the similarity between 4d SU(N) and 2d CP^N-1 theories does not hold for N=2.

Discussions

• "N=2 is large" (Ryuichiro Kitano, Ryutaro Matsudo, Norikazu Yamada, Masahito Yamazaki) https://arxiv.org/abs/2102.08784 [bsky, 1 points, 0 comments]

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