arXiv subjects

D. Miguélez-Caballero

Publications and source records attributed to D. Miguélez-Caballero.

9 recordsLinked to original sources

arXiv2026

Vortex clusters and vortex-filled bubbles in a modified Abelian-Higgs model

We investigate a single-component Abelian-Higgs model with an eighth-order scalar potential whose vacuum manifold consists of two disconnected circles. The model supports two species of vortices and domain walls interpolating between the two vacuum components. We find type-1.5-like behavior characterized by nonmonotonic intervortex interactions and bound states of spatially separated vortices. Inner-vacuum vortices form clusters through short-range repulsion and long-range attraction, whereas outer-vacuum vortices form vortex-filled bubbles in which a closed domain wall confines multiple inner-vacuum-vortex cores. We construct the domain wall analytically, derive the asymptotic vortex-wall interactions, and analyze the fluctuation spectra of coincident multivortices to identify their splitting instabilities.

hep-th↗

arXiv2026

Oscillons in the broken vacuum and global vortex annihilation

In contrast to the complex $ϕ^4$ model, vortex-antivortex collisions in the complex $ϕ^6$ theory reveal a resonant structure due to the existence of a remarkably stable, long-lived, large amplitude oscillon in the broken vacuum. Surprisingly, it persists despite the absence of a mass gap associated with the flat direction in the broken vacuum. We demonstrate that its existence is related to a far-distance modification of the potential, namely, the appearance of an unbroken (false or true) vacuum.

hep-th↗

arXiv2026

Evolution and scattering of excited topological defects: Interaction between internal modes

This thesis presents an extensive analysis of the behavior of topological solitons when one or more of their internal modes are activated. The first part of this manuscript is devoted to the study of the simplest topological solitons in (1+1) dimensions: kinks. Specifically, we investigate how these solutions emit radiation when one of their internal modes is initially excited, within the framework of the double $ϕ^4$ model. The simplest kink solution in this theory exhibits a complex internal mode structure that depends on a coupling constant appearing in the potential governing the dynamics. We will show how the amplitude and frequency of the emitted radiation are affected by changes in this coupling constant. We also examine the dynamics of wobbling kink/antikink scattering when the kinks possess more than one internal mode. To this end, we study kink/antikink collisions in the context of the simplest kink solution arising in the MSTB model. This analysis sheds light on the resonant energy exchange mechanism, allowing energy transfer between internal modes and the translational mode. The second part of this thesis focuses on excited vortex solutions in (2+1) dimensions. We begin with a detailed study of the internal mode structure associated with vortex solutions in the Abelian-Higgs model. We demonstrate how the problem can be significantly simplified by choosing an appropriate angular dependence for the eigenfunctions. Furthermore, we investigate the radiation emitted by a vortex when its internal mode is initially activated. To achieve this, we extend the analytical techniques used in (1+1) dimensions to field theories defined in two spatial dimensions. This enables us to compute the radiation amplitude, its frequency, and the decay of the internal mode amplitude due to energy loss via radiation. All analytical results are contrasted with data from numerical simulations.

hep-th↗

arXiv2025

Spectral structure of fluctuations around $n$-vortices in the Abelian-Higgs model

We study in detail the internal structure of rotationally invariant higher-charge Abelian-Higgs vortices. The symmetry of the normal modes close to the critical regime for type II vortices determines the possible disintegration channels. The full internal mode structure is discussed, finding modes that conserve the vortex symmetry (Derrick type modes) and modes whose symmetry differs (multipolar modes).

hep-th↗

arXiv2025

Moduli space metric of the excited vortex

We show that the moduli space metric of a single vortex gets corrections because of the excitation of the radially symmetric shape mode. It leads to a non-zero amount of the shape mode carried by the vortex when moving with a constant velocity. However, due to the radial symmetry, this effect does not reproduce the Lorentz contraction of the moving vortex. We apply the Derrick mode approximation in order to recover the Lorentz contraction on the level of the collective model.

hep-th↗

arXiv2024

Scattering between orthogonally wobbling kinks

The resonant energy transfer mechanism, responsible for the presence of fractal patterns in the velocity diagrams of kink-antikink scattering, is analyzed for a family of two-component scalar field theory models, in which the kink solutions have two shape modes (one longitudinal and one orthogonal to the kink orbit), in addition to the zero mode, and in which energy redistribution can occur among these three discrete modes. We investigate the scattering between wobbling kinks whose orthogonal shape mode is initially excited, examining how the final velocities, amplitudes, and frequencies depend on the initial excitation amplitude. The differences that this model presents with respect to the $ϕ^4$ model and its novel properties are highlighted. This analysis sheds light on the intricate dynamics that arise from the interplay between multiple degrees of freedom in kink scattering processes, offering insights distinct from those observed in simpler models.

hep-th↗

arXiv2024

Excited Abelian-Higgs vortices: decay rate and radiation emission

The evolution of 1-vortices when their massive bound mode is excited is investigated in detail (both analytically and numerically) in the Abelian-Higgs model for different ranges of the self-coupling constant. The dependence of the spectrum of the 1-vortex fluctuation operator on the model parameter is discussed initially. A perturbative approach is employed to study the radiation emission in both the scalar and the vector channels. Our findings reveal that the oscillating initial configuration of the 1-vortex radiates at a frequency twice that of the internal mode. Through energy conservation considerations, we derive the decay law of the massive mode. Finally, these analytical results are compared with numerical simulations in field theory.

hep-th↗

arXiv2023

Wobbling kinks and shape mode interactions in a coupled two-component $ϕ^4$ theory

The dynamics of a wobbling kink in a two-component coupled $ϕ^4$ scalar field theory (with an excited orthogonal shape mode) is addressed. For this purpose, the vibration spectrum of the second order small kink fluctuation is studied in order to find the corresponding vibration modes associated to the first (longitudinal) and second (orthogonal) field components. By means of this analysis, it was found that the number of possible shape modes depends on the value of the coupling constant. It is notable that when one of the orthogonal field shape modes is initially triggered, the unique shape mode of the longitudinal field is also activated. This coupling causes the kink to emit radiation with twice the frequency of excited mode in the first field component. Meanwhile, in the orthogonal channel we find radiation with two different frequencies: one is three times the frequency of the orthogonal wobbling mode and another is the sum of the frequencies of the longitudinal shape mode and the triggered mode. All the analytical results obtained in this study have been successfully contrasted with those obtained through numerical simulations.

nlin.PS↗

arXiv2022

Wobbling kinks in a two-component scalar field theory: Interaction between shape modes

In this paper the interaction between the shape modes of the wobbling kinks arising in the family of two-component MSTB scalar field theory models is studied. The spectrum of the second order small kink fluctuation in this model has two localized vibrational modes associated to longitudinal and orthogonal fluctuations with respect to the kink orbit. It has been found that the excitation of the orthogonal shape mode immediately triggers the longitudinal one. In the first component channel the kink emits radiation with twice the orthogonal wobbling frequency (not the longitudinal one as happens in the $ϕ^4$-model). The radiation emitted in the second component has two dominant frequencies: one is three times the frequency of the orthogonal wobbling mode and the other is the sum of the frequencies of the longitudinal and orthogonal vibration modes. This feature is explained analytically using perturbation expansion theories.

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