Evidence of a CP broken deconfined phase in 4D SU(2) Yang-Mills theory at θ = π from imaginary θ simulations
Abstract The spontaneous breaking of CP symmetry in 4D SU(N) pure Yang-Mills theory at θ = π has recently attracted much attention in the context of the higher-form symmetry and the ’t Hooft anomaly matching condition. Here we use Monte Carlo simulations to study the N = 2 case, which is interesting...
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| Format: | Article |
| Language: | English |
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SpringerOpen
2025-05-01
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| Series: | Journal of High Energy Physics |
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| Online Access: | https://doi.org/10.1007/JHEP05(2025)009 |
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| author | Mitsuaki Hirasawa Masazumi Honda Akira Matsumoto Jun Nishimura Atis Yosprakob |
| author_facet | Mitsuaki Hirasawa Masazumi Honda Akira Matsumoto Jun Nishimura Atis Yosprakob |
| author_sort | Mitsuaki Hirasawa |
| collection | DOAJ |
| description | Abstract The spontaneous breaking of CP symmetry in 4D SU(N) pure Yang-Mills theory at θ = π has recently attracted much attention in the context of the higher-form symmetry and the ’t Hooft anomaly matching condition. Here we use Monte Carlo simulations to study the N = 2 case, which is interesting since it is the case opposite to the large-N limit, where explicit calculations are available. In order to circumvent the severe sign problem due to the θ term for real θ, we first obtain results at imaginary θ, where the sign problem is absent, and make an analytic continuation to real θ. We use the stout smearing in defining the θ term in the action to be used in our simulations. Thus we obtain the expectation value of the topological charge and the deconfining temperature at θ = π, and provide evidence that the CP symmetry, which is spontaneously broken at low temperature, gets restored strictly above the deconfining temperature. This conclusion is consistent with the anomaly matching condition and yet differs from the prediction in the large-N limit. |
| format | Article |
| id | doaj-art-617eb8dba2de4a31a6917a255a887f97 |
| institution | DOAJ |
| issn | 1029-8479 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj-art-617eb8dba2de4a31a6917a255a887f972025-08-20T03:10:27ZengSpringerOpenJournal of High Energy Physics1029-84792025-05-012025512810.1007/JHEP05(2025)009Evidence of a CP broken deconfined phase in 4D SU(2) Yang-Mills theory at θ = π from imaginary θ simulationsMitsuaki Hirasawa0Masazumi Honda1Akira Matsumoto2Jun Nishimura3Atis Yosprakob4Department of Physics, University of Milano-BicoccaYukawa Institute for Theoretical Physics, Kyoto UniversityYukawa Institute for Theoretical Physics, Kyoto UniversityKEK Theory Center, High Energy Accelerator Research Organization (KEK)Department of Physics, Niigata UniversityAbstract The spontaneous breaking of CP symmetry in 4D SU(N) pure Yang-Mills theory at θ = π has recently attracted much attention in the context of the higher-form symmetry and the ’t Hooft anomaly matching condition. Here we use Monte Carlo simulations to study the N = 2 case, which is interesting since it is the case opposite to the large-N limit, where explicit calculations are available. In order to circumvent the severe sign problem due to the θ term for real θ, we first obtain results at imaginary θ, where the sign problem is absent, and make an analytic continuation to real θ. We use the stout smearing in defining the θ term in the action to be used in our simulations. Thus we obtain the expectation value of the topological charge and the deconfining temperature at θ = π, and provide evidence that the CP symmetry, which is spontaneously broken at low temperature, gets restored strictly above the deconfining temperature. This conclusion is consistent with the anomaly matching condition and yet differs from the prediction in the large-N limit.https://doi.org/10.1007/JHEP05(2025)009Lattice Quantum Field TheoryNon-Zero Temperature and DensitySpontaneous Symmetry Breaking |
| spellingShingle | Mitsuaki Hirasawa Masazumi Honda Akira Matsumoto Jun Nishimura Atis Yosprakob Evidence of a CP broken deconfined phase in 4D SU(2) Yang-Mills theory at θ = π from imaginary θ simulations Journal of High Energy Physics Lattice Quantum Field Theory Non-Zero Temperature and Density Spontaneous Symmetry Breaking |
| title | Evidence of a CP broken deconfined phase in 4D SU(2) Yang-Mills theory at θ = π from imaginary θ simulations |
| title_full | Evidence of a CP broken deconfined phase in 4D SU(2) Yang-Mills theory at θ = π from imaginary θ simulations |
| title_fullStr | Evidence of a CP broken deconfined phase in 4D SU(2) Yang-Mills theory at θ = π from imaginary θ simulations |
| title_full_unstemmed | Evidence of a CP broken deconfined phase in 4D SU(2) Yang-Mills theory at θ = π from imaginary θ simulations |
| title_short | Evidence of a CP broken deconfined phase in 4D SU(2) Yang-Mills theory at θ = π from imaginary θ simulations |
| title_sort | evidence of a cp broken deconfined phase in 4d su 2 yang mills theory at θ π from imaginary θ simulations |
| topic | Lattice Quantum Field Theory Non-Zero Temperature and Density Spontaneous Symmetry Breaking |
| url | https://doi.org/10.1007/JHEP05(2025)009 |
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