Strong CP problem in the quantum rotor
| Autor: | Albandea, David, Catumba, Guilherme, Ramos, Alberto |
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| Rok vydání: | 2024 |
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| Zdroj: | Phys. Rev. D 110 (2024) no.9, 094512 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevD.110.094512 |
| Popis: | Recent studies have claimed that the strong $CP$ problem does not occur in QCD, proposing a new order of limits in volume and topological sectors when studying observables on the lattice. In order to shed light on this issue, we study the effect of the topological $\theta$-term on a simple quantum mechanical rotor that allows a lattice description. The topological susceptibility and the $\theta$-dependence of the energy spectrum are both computed using local lattice correlation functions. The sign problem is overcome by considering Taylor expansions in $\theta$ exploiting automatic differentiation methods for Monte Carlo processes. Our findings confirm the conventional wisdom on the strong $CP$ problem. Comment: 11 pages, 6 figures. v2: edit to match published version |
| Databáze: | arXiv |
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