arXiv subjects

Gabriel Luchini

Publications and source records attributed to Gabriel Luchini.

4 recordsLinked to original sources

arXiv2020

Some novel considerations about the collective coordinates approximation for the scattering of $ϕ^4$ kinks

The collective coordinates approximation for the kink/anti-kink scattering in the $1+1$ dimensional $ϕ^4$ model is considered and we discuss how the results found in the current literature on the topic can be improved by giving the analytical expression for the lagrangian in the space of parameters. A comprehensive discussion of the role of the collective coordinates approximation in this particular situation is given for completeness.

hep-th↗

arXiv2020

Real scalar field kink(-antikink)s and their perturbation spectra in a closed universe

In this paper we demonstrate that solitons of a simple real scalar field model that are {\it static and linearly stable} do exist when considered in a (3+1)-dimensional, spatially compact space-time background, the static Einstein universe, which is a good approximation to the observed universe for sufficiently small time intervals. We study the properties of these solutions for a $Φ^4$-potential and demonstrate that next to the fundamental solutions, excited configurations exist. We also investigate general perturbations about the solitons, determine their eigenfrequency spectra and compare them with those of the perturbations about the vacua of the model. We find that the degeneracy with respect to the multipoles of the perturbation, which is present for the vacua, does no longer exist in the presence of the soliton. Moreover, specific perturbations correspond to zero modes of the system. Our results have applications in condensed matter physics as well as computations of quantum effects (e.g. the Casimir energy) in spatially compact space-times in the presence of soliton-like objects.

hep-th↗

arXiv2015

From topological to non-topological solitons: kinks, domain walls and Q-balls in a scalar field model with non-trivial vacuum manifold

We consider a scalar field model with a self-interaction potential that possesses a discrete vacuum manifold. We point out that this model allows for both topological as well as non-topological solitons. In (1+1) dimensions both type of solutions have finite energy, while in (3+1) dimensions, the topological solitons have finite energy per unit area only and correspond to domain walls. Non-topological solitons with finite energy do exist in (3+1) dimensions due to a non-trivial phase of the scalar field and an associated U(1) symmetry of the model, though. We construct these so-called Q-ball solutions numerically, point out the differences to previous studies with different scalar field potentials and also discuss the influence of a minimal coupling to both gravity as well as a U(1) gauge field. In this latter case, the conserved Noether charge Q can be interpreted as the electric charge of the solution.

hep-th↗

arXiv2010

The Hilbert space of Chern-Simons theory on the cylinder. A Loop Quantum Gravity approach

As a laboratory for loop quantum gravity, we consider the canonical quantization of the three-dimensional Chern-Simons theory on a noncompact space with the topology of a cylinder. Working within the loop quantization formalism, we define at the quantum level the constraints appearing in the canonical approach and completely solve them, thus constructing a gauge and diffeomorphism invariant physical Hilbert space for the theory. This space turns out to be infinite dimensional, but separable.

gr-qc↗