arXiv subjects

A. C. Amaro de Faria Jr.

Publications and source records attributed to A. C. Amaro de Faria Jr..

5 recordsLinked to original sources

arXiv2018

Testing Lorentz symmetry violation with an invariant minimum speed

This work presents an experimental test of Lorentz invariance violation in the infrared (IR) regime by means of an invariant minimum speed in the spacetime and its effects on the time when an atomic clock given by a certain radioactive single-atom (e.g.: isotope $Na^{25}$) is a thermometer for a ultracold gas like the dipolar gas $Na^{23}K^{40}$. So, according to a Deformed Special Relativity (DSR) so-called Symmetrical Special Relativity (SSR), where there emerges an invariant minimum speed $V$ in the subatomic world, one expects that the proper time of such a clock moving close to $V$ in thermal equilibrium with the ultracold gas is dilated with respect to the improper time given in lab, i.e., the proper time at ultracold systems elapses faster than the improper one for an observer in lab, thus leading to the so-called {\it proper time dilation} so that the atomic decay rate of a ultracold radioactive sample (e.g: $Na^{25}$) becomes larger than the decay rate of the same sample at room temperature. This means a suppression of the half-life time of a radioactive sample thermalized with a ultracold cloud of dipolar gas to be investigated by NASA in the Cold Atom Lab (CAL).

physics.gen-ph↗

arXiv2016

Asymptotic freedom and quarks confinement treated through Thompson's approach

In this work, we first use Thompson's renormalization group method to treat QCD-vacuum behavior close to the regime of asymptotic freedom. QCD-vacuum behaves effectively like a "paramagnetic system" of a classical theory in the sense that virtual color charges (gluons) emerge in it as spin effect of a paramagnetic material when a magnetic field aligns their microscopic magnetic dipoles. Making a classical analogy with the paramagnetism of Landau's theory,we are able to introduce a kind of Landau effective action without temperature and phase transition for simply representing QCD-vacuum behavior at higher energies as magnetization of a paramagnetic material in the presence of a magnetic field H. This reasoning allows us to use Thompson's heuristic approach in order to extract an "effective susceptibility" ($χ>0$) of QCD-vacuum. It depends on logarithmic of energy scale u to investigate hadronic matter. Consequently,we are able to get an "effective magnetic permeability" ($μ>1$) of such a "paramagnetic vacuum". As QCD-vacuum must obey Lorentz invariance,the attainment of $μ>1$ must simply require that the "effective electrical permissivity" is $ε<1$,in such a way that $με=1$ (c^2=1).This leads to the antiscreening effect, where the asymptotic freedom takes place. On the other hand, quarks cofinement, a subject which is not treatable by perturbative calculations, is worked by the present approach. We apply the method to study this subject in order to obtain the string constant, which is in agreement with the experiments.

hep-ph↗

arXiv2009

Degenerate and critical domain walls and accelerating universes driven by bulk particles

We consider a scenario where our universe is taken as a three-dimensional domain wall embedded in a five-dimensional Minkowski space-time, as originally proposed by Brito and collaborators [1]. We explore the existence of a richer class of soliton solutions and their consequences for the acceleration of the universe driven by collisions of bulk particle excitations with the walls. In particular it is shown that some of these solutions should play a fundamental role throughout the expansion process.

hep-th↗

arXiv2008

Degenerate and critical Bloch branes

In the last few years a number of works reported the appearance of thick branes with internal structure, induced by the parameter which controls the interaction between two scalar fields coupled to gravity in (4,1) dimensions in warped space-time with one extra dimension. Here we show that one can implement the control over the brane thickness without needing to change the potential parameter. On the contrary, this is going to be done by means of the variation of a parameter associated to the domain wall degeneracy. We also report the existence of novel and qualitatively different solutions for a critical value of the degeneracy parameter, which could be called critical Bloch branes.

hep-th↗

arXiv2007

Vacuumless kinks systems from vacuum ones, an example

Some years ago, Cho and Vilenkin, introduced a model which presents topological solutions, despite not having degenerate vacua as is usually expected. Here we present a new model with topological defects, connecting degenerate vacua but which in a certain limit recovers precisely the one proposed originally by Cho and Vilenkin. In other words, we found a kind of parent model for the so called vacuumless model. Then the idea is extended to a model recently introduced by Bazeia et al. Finally, we trace some comments the case of the Liouville model.

hep-th↗