Manuel Torres-Labansat

arXiv2024

Multi-kinks and composite oscillons in a commensurable and non degenerate double sine-Gordon model

In this paper, we introduce a commensurable and non-degenerate double sine-Gordon model, in which a partial breaking of vacuum degeneracy provides a mechanism for the emergence of static multi-kinks. These multi-kinks $K_n$ are stable field configurations with internal structure, consisting of $n$ localized energy packets with well-defined separations. The properties of the multi-kinks are thoroughly analyzed, including the novel phenomenology that arises during their collisions. In particular, we observe the emergence of long-lived composite oscillons that reflect the original structure of the multi-kinks. The sub-kink's positions and their vibration modes provide collective coordinates that are used to construct a phenomenological model, which offers a good qualitative explanation of the observed oscillon properties. Radiation effects are consistently incorporated, revealing that they play an important role in the observed synchronization of the oscillon's vibrational components.

hep-th↗

arXiv2021

Kink solutions in a generalized scalar $ϕ^4_G$ field model

We study a scalar field model in a two dimensional space-time with a generalized $ϕ^4_G$ potential which has four minima, obtaining novel kink solutions with well defined properties although the potential is non-analytical at the origin. The model contains a control parameter $δ$ that breaks the degeneracy of the potential minima, giving rise to two different phases for the system. The $δ<0$ phases do not possess solitary wave solutions. At the transition point $δ=0$ all the potential minima are degenerate and three different kink solutions result. As the transition to the $δ>0$ phase takes place, the minima of the potential are no longer degenerate and a unique kink $ϕ_δ$ solution is produced. Remarkably, this kink is a coherent structure that results from the merge of three kinks that can be identified with those observed at the transition point. To support the interpretation of $ϕ_δ$ as a bound state of three kinks, we calculate the force between the kink-kink pair components of $ϕ_δ$, obtaining an expression that has both exponentially repulsive and constant attractive contributions that yields an equilibrium configuration, explaining the formation of the $ϕ_δ$ multi-kink state. We further investigate kink properties including their stability guaranteed by the positive defined spectrum of small fluctuations around the kink configurations. The findings of our work together with a semiclassical WKB quantization, including the one loop mass renormalization, enable computing quantum corrections to the kink masses. The general results could be relevant to the development of effective theories for non-equilibrium steady states and for the understanding of the formation of coherent structures.

hep-th↗