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arXiv · 2507.01082

PQ-ball and its Real Scalar Analogue in an Expanding Universe

Kazunori Nakayama·Masaki Yamada
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Abstract

We demonstrate the formation of quasi-stable localized scalar configurations in spontaneously symmetry breaking U(1) model by 3+1-dimensional classical lattice simulations. Such configurations are called PQ-balls, as the primary motivation of this kind of configuration is Peccei-Quinn theory under the kinetic misalignment mechanism. Our numerical simulations demonstrate that they can form if the PQ charge is generated through the coherent rotation of a complex scalar field in the complex plane, via dynamics analogous to the Affleck-Dine mechanism. These configurations subsequently decay due to the U(1)-breaking effect induced by spontaneous symmetry breaking. We also demonstrate the formation and decay of oscillons in a similar setup in a real scalar field theory.

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Kazunori Nakayama, Masaki Yamada. 2025-07-01. PQ-ball and its Real Scalar Analogue in an Expanding Universe. https://arxiv.org/abs/2507.01082

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