arXiv subjects

S. Miraboutalebi

Publications and source records attributed to S. Miraboutalebi.

8 recordsLinked to original sources

arXiv2024

The modulated soliton fields in the Goldstone boson model

It is well known that massless Goldstone bosons have not yet been observed. In the Goldstone boson model, after the spontaneous symmetry breaking under $U(1)$, two coupled nonlinear equations are obtained for which we present the exact solitonic solutions. These solutions completely localize the energy density of the model and show the existence of two boson fields, one massive and the other massless. Also, it is seen that the solitonic waves are modulated and the massless wave rides on the massive wave. Finally, we calculate the charge density of the model, which again confirms the neutrality of these boson fields. Since massive bosons can be observed in the laboratory, these solitonic waves may be useful in tracking and detecting Goldstone bosons.

hep-th↗

arXiv2022

Effect of RGUP on the nonlinear Klein-Gordon model with spontaneous symmetry breaking

In the framework of the relativistic generalized uncertainty principle (RGUP), we study the nonlinear Klein-Gordon field with $ϕ^4$ self-interaction. This generalization comes from the quantum gravity theories that predict the existence of a minimal measurable length scale. The quantum gravity effects slightly modify the momentum and change the Lagrangian density of the field. This model, specifically in the context of spontaneous symmetry breaking, is so fruitful and leads us to many interesting phenomena. Due to the complexity of the consequent equations, the model is normally studied via perturbation mechanisms. However, here, we apply a generalized $tanh$-method which supposed that the field solutions should be $sech$-functions of segments of space and time. By this extended method, we find some more general solutions with respect to our previous work \cite{Mir1}. Several solutions can be found but we select only the normalizable and bounded solitary fields. The energy spectrum of each field solution is obtained in an analytical form and discussed. The modification parameter of the corresponding RGUP is estimated by using the rest energy of the mass of the Higgs boson.

hep-th↗

arXiv2022

Quantum coherence in neutrino oscillation in matter

A closer and more detailed study of neutrino oscillation, in addition to assisting us in founding physics beyond the standard model, can potentially be used to understand the fundamental aspects of quantum mechanics. In particular, we know that the neutrino oscillation occurs because the quantum states of the produced and detected neutrinos are a coherent superposition of the mass eigenstates, and this coherency is maintained during the propagation due to the small mass difference of neutrinos. In this paper, we consider the decoherence due to the neutrino interaction in the material medium with constant density in addition to the decoherence coming from the localization properties. For this purpose, we use $l_1\text{-norm}$ in order to quantify the coherence and investigate its dependence on the matter density. According to our results, in general, the coherence in material medium is less than vacuum. However, there exist exceptions; for some matter densities, the localization coherence lengths become infinite. So, for these cases, $l_1\text{-norm}$ in matter is more than the vacuum.

quant-ph↗

arXiv2021

The solitary solutions of nonlinear Klein-Gordon field with minimal length

The existence of a minimal length is predicted by theories of quantum gravity and it is generally accepted that this minimal length should be of the order of the Planck length and hence can be observed in high energy phenomenon. We study the implications of the presence of the minimal length on the Klein-Gordon filed with ϕ4self-interaction. Considering the process of spontaneous symmetry breaking, the potential also includes the ϕ3term. The consequent field equation is a fourth-order differential equation and is considered to have solitary solutions. The sech method is applied and the normalized solutions are obtained in closed forms and the energy spectrum of the solitary fields is determined. The modification parameter of the theory is estimated by the width and the energy of the obtained solitary fields.

hep-th↗

arXiv2020

Solutions of N-dimensional Schrödinger Equation with Morse Potential Via Laplace Transforms

A study is undertaken to investigate an analytical solution for the N-dimensional Schrödinger equation with the Morse potential based on the Laplace transformation method. The results show that in the Pekeris approximation, the radial part of the Schrödinger equation reduces to the corresponding equation in one dimension. Hence its exact solutions can be obtained by the Laplace transformation method of G. Chen, phys. Lett. A 326 (2004) 55. In addition, a comparison is made between the energy spectrum resulted from this method and the spectra that are obtained from the two-point quasi-rational approximation method and the Nikiforov-Uvarov approach.

quant-ph↗

arXiv2019

Phase transition of modified Horndeski gravity with new method

In this paper, we investigate the critical points of the $ P-V $ diagram and the phase transitions of the Horndenski black holes. In fact, the usual Horndeski black holes do not have $ P-V $ critical points, hence do not show any phase transitions. However, we successfully modify the Horndeski black hole solution to obtain such a phase transition behavior. This modified black holes solution is satisfied by the equation of state of liquid-gas phase transition. Also, we study the thermodynamics of our modified Horndeski black hole by applying a new method based on the equation of state that originated from the slope of temperature versus entropy. This new prescription provides us a simple powerful way to study the critical behavior and the phase transition of the black holes and concludes the novel results. The analytical interpretation of possible phase transition points leads us to set some nonphysical range on the horizon radius for the black hole.

gr-qc↗

arXiv2019

Charged accelerating AdS black hole of $f(R)$ gravity and the Joule-Thomson expansion

In this paper, the thermodynamical properties and the phase transitions of the charged accelerating anti-de Sitter (AdS) black holes are investigated in the framework of the $f(R)$ gravity. By studying the conditions for the phase transitions, it has been shown that the $P-V$ criticality and the van der Waals like phase transitions can be achieved for $ T \approx T_{c} $. The Joule-Thomson expansion effects are also examined for the charged accelerating AdS black holes of the $f(R)$ gravity. Here, we derive the inversion temperatures as well as the inversion curves. Then, we determine the position of the reverse point for different values of mass $M$ and parameter $b$ for the corresponding black hole. At this point, the Joule-Thompson coefficient is zero. So, in such case, we can say that such point is very important for the finding of cooling - heating regions. Finally, we calculate the ratio of minimum inversion temperature and critical temperature for such black hole.

gr-qc↗

arXiv2019

The temperature and entropy corrections on the charged hairy black holes

In this paper, we consider the first order correction of the entropy and temperature in a charged black hole with a scalar field. Here, we apply such correction for the different cases of black holes. These corrections are due to the thermal fluctuations of statistical physics. Also, we take advantage of such corrections and study the $ P - V $ critically and phase transition. Also, we investigate the effect of correction on the critical point and stability of the system. We obtain modified thermodynamics quantities and find effects of thermal fluctuations in the stability of the black hole. We find that stability of black hole is depend on the thermal fluctuations. Finally, we compare the results of the corrected and uncorrected by thermodynamical quantities.

gr-qc↗