Interacting Q-balls

TL;DR

This paper explores new types of Q-ball solutions, including axially symmetric and interacting configurations, revealing their properties, energy structures, and existence conditions through numerical methods.

Contribution

It introduces novel axially symmetric Q-ball solutions and investigates their interactions, expanding the understanding of non-topological solitons in scalar field models.

Findings

New axially symmetric, non-spinning Q-ball solutions constructed numerically.

Identification of two types of 2-Q-ball solutions with different symmetries.

Analysis of energy, charge, and parameter dependence of interacting Q-balls.

Abstract

We study non-topological solitons, so called Q-balls, which carry a non-vanishing Noether charge and arise as lump solutions of self-interacting complex scalar field models. Explicit examples of new axially symmetric non-spinning Q-ball solutions that have not been studied so far are constructed numerically. These solutions can be interpreted as angular excitations of the fundamental $Q$-balls and are related to the spherical harmonics. Correspondingly, they have higher energy and their energy densities possess two local maxima on the positive z-axis. We also study two Q-balls interacting via a potential term in (3+1) dimensions and construct examples of stationary, solitonic-like objects in (3+1)-dimensional flat space-time that consist of two interacting global scalar fields. We concentrate on configurations composed of one spinning and one non-spinning Q-ball and study the parameter-dependence of the energy and charges of the configuration. In addition, we present numerical evidence that for fixed values of the coupling constants two different types of 2-Q-ball solutions exist: solutions with defined parity, but also solutions which are asymmetric with respect to reflexion through the x-y-plane.