Compact Q-balls and Q-shells in a multi-component $\mathbb{C}P^N$ model

Abstract

Coupled multi-component $\mathbb{C}P^N$ models with V-shaped potentials are analyzed. It is shown that the model has solutions being combinations of compact Q-balls and Q-shells. The compact nature of solutions permits the existence of novel harbor-type solutions having the form of Q-balls sheltered by Q-shells. The relation between the energy $E$ and Noether charge $Q$ is discussed both analytically and numerically. The energy of the solutions behaves as $E\sim |Q|^\alpha,~\alpha<1$, i.e., as for the standard Q-ball. Furthermore, the ratio $E/Q$ for various configurations in the multi-component model suggests that the solutions are at least classically stable.