B. Çil, I. Çevik, G. D. A. Yildiz, E. Kara, E. Gudekli
In this study, we examined the horizon problem in the Bianchi type- V cosmological model. Our investigation showed that we could not obtain the solution to the horizon problem without neglecting the strong energy condi- tion. As a result, we have shown no horizon problem in our model with figures and calculations.
{"title":"Horizon Problem for Bianchi Type-V Universe Model","authors":"B. Çil, I. Çevik, G. D. A. Yildiz, E. Kara, E. Gudekli","doi":"10.1139/cjp-2022-0076","DOIUrl":"https://doi.org/10.1139/cjp-2022-0076","url":null,"abstract":"In this study, we examined the horizon problem in the Bianchi type- V cosmological model. Our investigation showed that we could not obtain the solution to the horizon problem without neglecting the strong energy condi- tion. As a result, we have shown no horizon problem in our model with figures and calculations.","PeriodicalId":9413,"journal":{"name":"Canadian Journal of Physics","volume":"27 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83221712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Malik, Mushtaq Ahmad, Basem Abdullah M. Al Alwan, Zahra Naeem
The goal of this work was to investigate the behavior of charge compact stars in the context of [Formula: see text] theory of gravity, which is one of the most powerful candidates responsible for the accelerated expansion of the universe. The salient feature of the current research is the consideration of Bardeen’s model, which describes an exterior space–time and interprets the magnetic monopole arising from gravity collapse caused by some specific conditions of nonlinear electrodynamics. Moreover, we analyzed the structure of the star by using the solution provided by a Finch–Skea-type metric potential. All the physically necessary parameters and characteristics of relativistic spheres are displayed graphically. We further studied the energy density, pressure curves, equation-of-state parameters, anisotropy factor, energy conditions, Tolman–Oppenheimer–Volkoff equation, redshift functions, compactness parameters, adiabatic index, and stability analysis in detail.
{"title":"Bardeen compact stars in modified f(G) gravity","authors":"A. Malik, Mushtaq Ahmad, Basem Abdullah M. Al Alwan, Zahra Naeem","doi":"10.1139/cjp-2021-0411","DOIUrl":"https://doi.org/10.1139/cjp-2021-0411","url":null,"abstract":"The goal of this work was to investigate the behavior of charge compact stars in the context of [Formula: see text] theory of gravity, which is one of the most powerful candidates responsible for the accelerated expansion of the universe. The salient feature of the current research is the consideration of Bardeen’s model, which describes an exterior space–time and interprets the magnetic monopole arising from gravity collapse caused by some specific conditions of nonlinear electrodynamics. Moreover, we analyzed the structure of the star by using the solution provided by a Finch–Skea-type metric potential. All the physically necessary parameters and characteristics of relativistic spheres are displayed graphically. We further studied the energy density, pressure curves, equation-of-state parameters, anisotropy factor, energy conditions, Tolman–Oppenheimer–Volkoff equation, redshift functions, compactness parameters, adiabatic index, and stability analysis in detail.","PeriodicalId":9413,"journal":{"name":"Canadian Journal of Physics","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79490666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chaotic motion of electrons causes a considerable decrease in gain and efficiency of free-electron lasers (FELs). In this paper, we study chaotic dynamic of electrons moving with relativistic velocity in a realizable (three-dimensional) quadrupole wiggler when the radial dependency of wiggler magnetic field is fully taken into account using time series, Poincaré surface-of-section maps and Liapunov exponents. The electron beam is also considered to be realizable with Gaussian density profile and an ion-channel is considered as a guiding device for electron beam. We show that the chaotic behavior of electron motion is due to the nonlinearity of quadrupole wiggler magnetic field and the chaotic electron motion occurs at almost large radial distances in which the wiggler magnetic field is large. Also, we find that one can control the electron chaotic motion by using electron beam with Gaussian density rather than the electron beam with uniform density. Furthermore, we investigate the effect of ion-channel and find that when the electrostatic force of ion-channel overcomes the non-linearity effect of quadrupole wiggler magnetic field and self-repulsive force arises from electron beam, the electron motion becomes non-chaotic. We also investigate the electron motion under Budker condition and show that the Budker condition cannot guarantee the electron motion becomes completely non-chaotic.
{"title":"Chaotic electron dynamic in a FEL with realizable quadrupole wiggler and Gaussian electron beam","authors":"Amin Taghavi, M. Esmaeilzadeh","doi":"10.1139/cjp-2021-0053","DOIUrl":"https://doi.org/10.1139/cjp-2021-0053","url":null,"abstract":"Chaotic motion of electrons causes a considerable decrease in gain and efficiency of free-electron lasers (FELs). In this paper, we study chaotic dynamic of electrons moving with relativistic velocity in a realizable (three-dimensional) quadrupole wiggler when the radial dependency of wiggler magnetic field is fully taken into account using time series, Poincaré surface-of-section maps and Liapunov exponents. The electron beam is also considered to be realizable with Gaussian density profile and an ion-channel is considered as a guiding device for electron beam. We show that the chaotic behavior of electron motion is due to the nonlinearity of quadrupole wiggler magnetic field and the chaotic electron motion occurs at almost large radial distances in which the wiggler magnetic field is large. Also, we find that one can control the electron chaotic motion by using electron beam with Gaussian density rather than the electron beam with uniform density. Furthermore, we investigate the effect of ion-channel and find that when the electrostatic force of ion-channel overcomes the non-linearity effect of quadrupole wiggler magnetic field and self-repulsive force arises from electron beam, the electron motion becomes non-chaotic. We also investigate the electron motion under Budker condition and show that the Budker condition cannot guarantee the electron motion becomes completely non-chaotic.","PeriodicalId":9413,"journal":{"name":"Canadian Journal of Physics","volume":"32 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85067869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We suggest a renormalizable Standard model extension based on S4 symmetry which accommodates the recent observed neutrino oscillation pattern. Through the type-I seesaw mechanism, the smallness of the active neutrino mass and its hierarchy are produced. The model generates the the updated data on neutrino parameters in which 1 σ range of the reactor neutrino mixing angle θ13, the atmospheric neutrino mixing θ23 and the Dirac phase δ for both NH and IH while for the solar mixing angle θ12 = 35.70° belongs to 2σ range. The effective masses are found to be (mee) = 5.74 meV for NH and (mee) = 48.1meV for IH within their allowed constraints.
{"title":"Renormalizable Standard Model Extension with S4 symmetry for neutrino mass and mixing","authors":"V. V. Vien","doi":"10.1139/cjp-2022-0009","DOIUrl":"https://doi.org/10.1139/cjp-2022-0009","url":null,"abstract":"We suggest a renormalizable Standard model extension based on S4 symmetry which accommodates the recent observed neutrino oscillation pattern. Through the type-I seesaw mechanism, the smallness of the active neutrino mass and its hierarchy are produced. The model generates the the updated data on neutrino parameters in which 1 σ range of the reactor neutrino mixing angle θ13, the atmospheric neutrino mixing θ23 and the Dirac phase δ for both NH and IH while for the solar mixing angle θ12 = 35.70° belongs to 2σ range. The effective masses are found to be (mee) = 5.74 meV for NH and (mee) = 48.1meV for IH within their allowed constraints.","PeriodicalId":9413,"journal":{"name":"Canadian Journal of Physics","volume":"10 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88113878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The evolution of the dark energy within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) model filled with barotropic fluid and dark energy is examined. We have considered the two cases of an interacting and non-interacting two-fluid (barotropic and dark energy) scenario and obtained the exact solutions to the corresponding field equations. In an interacting model we have considered linear as well as quadratic interaction between dark sector of the universe. We have also given the quadrature form for general interaction coupling parameter via Q = αρmn, n ≥ 1 and discussed the evolution of energy densities and effective equation of state with cosmic time for flat, closed and open universe. It is also examined that the matter energy density is dominated in early phase of the universe where as the dark energy density is dominated in later phase of the universe for both scenarios which is in concurrence with current observations.
{"title":"Aspects of Non-interacting and Interacting Universe: A Complete Scenario","authors":"R. Raushan, A. Shukla, R. Chaubey","doi":"10.1139/cjp-2021-0417","DOIUrl":"https://doi.org/10.1139/cjp-2021-0417","url":null,"abstract":"The evolution of the dark energy within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) model filled with barotropic fluid and dark energy is examined. We have considered the two cases of an interacting and non-interacting two-fluid (barotropic and dark energy) scenario and obtained the exact solutions to the corresponding field equations. In an interacting model we have considered linear as well as quadratic interaction between dark sector of the universe. We have also given the quadrature form for general interaction coupling parameter via Q = αρmn, n ≥ 1 and discussed the evolution of energy densities and effective equation of state with cosmic time for flat, closed and open universe. It is also examined that the matter energy density is dominated in early phase of the universe where as the dark energy density is dominated in later phase of the universe for both scenarios which is in concurrence with current observations.","PeriodicalId":9413,"journal":{"name":"Canadian Journal of Physics","volume":"85 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77909666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work discusses the responsible quantities of the emergence inhomogeneity by taking locally anisotropic radiating fluid in f(G, T ) theory of gravity, where G is the Gauss-Bonnet term and T is the trace of stress-energy tensor. The temporal and radial change in mass function is observed with the help of modified version of Einstein’s field equations. To observe the dynamics of self-gravitating fluid, the dynamical equations and differential equations for conformal tensor are formulated, which help to understand the role of correction terms, Weyl curvature and fluid parameter in the energy-density irregularity. Different aspects of fluid are considered to meet the desired results.
{"title":"Existence of Energy Density Homogeneity for Radiating Spheres in f (G, T ) Gravity","authors":"Z. Yousaf, M. Z. Bhatti, A. Farhat","doi":"10.1139/cjp-2022-0069","DOIUrl":"https://doi.org/10.1139/cjp-2022-0069","url":null,"abstract":"This work discusses the responsible quantities of the emergence inhomogeneity by taking locally anisotropic radiating fluid in f(G, T ) theory of gravity, where G is the Gauss-Bonnet term and T is the trace of stress-energy tensor. The temporal and radial change in mass function is observed with the help of modified version of Einstein’s field equations. To observe the dynamics of self-gravitating fluid, the dynamical equations and differential equations for conformal tensor are formulated, which help to understand the role of correction terms, Weyl curvature and fluid parameter in the energy-density irregularity. Different aspects of fluid are considered to meet the desired results.","PeriodicalId":9413,"journal":{"name":"Canadian Journal of Physics","volume":"21 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80126889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. S. Sheik Sirajuddeen, S. Beer Mohamed, N. Hajara Beevi, V. Ashwin, Ikram Un Nabi Lone
Half metallic ferromagnetism is reported in RbTiO3 and CsTiO3 compounds under the exchange correlation functions GGA, TB-mBJ and GGA+U using full potential linearized augmented plane wave method. Spin resolved calculations are carried out and implemented within the framework of density functional theory. The compounds exhibit energy band gap in spin up direction using three functional of PBE-GGA, TB-mBJ and GGA+U. A larger band gap is predicted to occur in both the compounds with the use of TB-mBJ potential. A higher value of magnetic moment is evidenced for RbTiO3 and CsTiO3 using PBE-GGA method as compared to mBJ and GGA+U methods. Curie temperature has been determined for the compounds at equilibrium and reduced volumes. It is reported that Curie temperature increases with the increase of hydrostatic pressure. With the help of second order elastic constants, Debye temperature and anisotropy factor have been predicted for the compounds.
{"title":"Spin resolved-Electronic, Magnetic and Thermodynamic properties of perovskites XTiO3 (X= Rb, Cs) using GGA, TB-mBJ and GGA+U Potentials -A DFT approach","authors":"M. S. Sheik Sirajuddeen, S. Beer Mohamed, N. Hajara Beevi, V. Ashwin, Ikram Un Nabi Lone","doi":"10.1139/cjp-2022-0056","DOIUrl":"https://doi.org/10.1139/cjp-2022-0056","url":null,"abstract":"Half metallic ferromagnetism is reported in RbTiO3 and CsTiO3 compounds under the exchange correlation functions GGA, TB-mBJ and GGA+U using full potential linearized augmented plane wave method. Spin resolved calculations are carried out and implemented within the framework of density functional theory. The compounds exhibit energy band gap in spin up direction using three functional of PBE-GGA, TB-mBJ and GGA+U. A larger band gap is predicted to occur in both the compounds with the use of TB-mBJ potential. A higher value of magnetic moment is evidenced for RbTiO3 and CsTiO3 using PBE-GGA method as compared to mBJ and GGA+U methods. Curie temperature has been determined for the compounds at equilibrium and reduced volumes. It is reported that Curie temperature increases with the increase of hydrostatic pressure. With the help of second order elastic constants, Debye temperature and anisotropy factor have been predicted for the compounds.","PeriodicalId":9413,"journal":{"name":"Canadian Journal of Physics","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79482090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper we extend Shaposhnikov et al parity violating Einstein-Cartan-Holst action by adding to Holst term H, a Proca photontorsion coupling χpt = 10−24 as computed by De Sabbata, Garcia de Andrade, and Sivaram. The strenght of Holst term is obtained, in the case of early universe torsion as T ∼ 1MeV gravity part is the Planck mass product with the Holst term. The photon mass in this case yields m2 γH ∼ 10−69GeV4. Therefore in the case, photon interacts very weakly with spin-torsion matter in Einstein-Cartan gravity, the strength of Maxwell-Proca-Holst interaction is much weaker than pure gravity sector. For dark photons this situation changes drastically since a dark photon mass reaches 1.5GeV , and from this mass and T = 10−3GeV , one obtains a Maxwell-Proca-Holst strenght of 10−6GeV 4, which is now comparable with the gravity sector. Dynamo mechanism competes with the chirality and dissipation by the handness of the magnetic field with respect to torsion trace vector, to regenerate the magnetic field decay. Bombacigno and Mantovani have recently found a sign of the Immirzi parameter in the Holst-Nieh-Yan extension of EC gravity. Here we also find torsion waves for the Immirzi inverse parameter and in the sense that this divergence of torsion trace is porportional to Immirzi field.].
{"title":"Einstein-Cartan-Holst-Proca Dynamos Massive Photons as Dark Matter and GWs","authors":"L. C. G. de Andrade","doi":"10.1139/cjp-2021-0406","DOIUrl":"https://doi.org/10.1139/cjp-2021-0406","url":null,"abstract":"In this paper we extend Shaposhnikov et al parity violating Einstein-Cartan-Holst action by adding to Holst term H, a Proca photontorsion coupling χpt = 10−24 as computed by De Sabbata, Garcia de Andrade, and Sivaram. The strenght of Holst term is obtained, in the case of early universe torsion as T ∼ 1MeV gravity part is the Planck mass product with the Holst term. The photon mass in this case yields m2 γH ∼ 10−69GeV4. Therefore in the case, photon interacts very weakly with spin-torsion matter in Einstein-Cartan gravity, the strength of Maxwell-Proca-Holst interaction is much weaker than pure gravity sector. For dark photons this situation changes drastically since a dark photon mass reaches 1.5GeV , and from this mass and T = 10−3GeV , one obtains a Maxwell-Proca-Holst strenght of 10−6GeV 4, which is now comparable with the gravity sector. Dynamo mechanism competes with the chirality and dissipation by the handness of the magnetic field with respect to torsion trace vector, to regenerate the magnetic field decay. Bombacigno and Mantovani have recently found a sign of the Immirzi parameter in the Holst-Nieh-Yan extension of EC gravity. Here we also find torsion waves for the Immirzi inverse parameter and in the sense that this divergence of torsion trace is porportional to Immirzi field.].","PeriodicalId":9413,"journal":{"name":"Canadian Journal of Physics","volume":"13 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79312751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Galperin [Regul. Chaotic. Dyn. 8, 375 (2003)] introduced an interesting method to learn the digits of π by counting the collisions of two billiard balls and a hard wall. This paper studies two quantum versions of the Galperin billiards. It is shown that the digits of π can be observed in the phase shifts of the quantum models.
{"title":"Hear π from Quantum Galperin Billiards","authors":"Y. Cai, Fu-Lin Zhang","doi":"10.1139/cjp-2022-0262","DOIUrl":"https://doi.org/10.1139/cjp-2022-0262","url":null,"abstract":"Galperin [Regul. Chaotic. Dyn. 8, 375 (2003)] introduced an interesting method to learn the digits of π by counting the collisions of two billiard balls and a hard wall. This paper studies two quantum versions of the Galperin billiards. It is shown that the digits of π can be observed in the phase shifts of the quantum models.","PeriodicalId":9413,"journal":{"name":"Canadian Journal of Physics","volume":"18 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85931737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Joule-Thomson expansion of Einstein-Skyrmion black holes in four dimensions is studied in the extended phase space. We obtain the inversion curves and the isenthalpic curves for different values of parameters K and λ, which represent the coupling strength between the gravity field and matter field. We find that the parameters K and λ have the same effects during the entire Joule-Thomson expansion and the bigger parameter K or λ corresponds to the smaller inversion pressure. Analogously, the phase space {T, P} consist of cooling-heating regions. In addition, the dispersion point of the Joule-Thomson coefficient µ is in correspondence with the zero point of the Hawking temperature T and the ratio of the minimum inversion temperature Tmini and the critical temperature is a constant.
{"title":"Joule-Thomson expansion of Einstein-Skyrmion black holes","authors":"Yan Bai","doi":"10.1139/cjp-2022-0062","DOIUrl":"https://doi.org/10.1139/cjp-2022-0062","url":null,"abstract":"The Joule-Thomson expansion of Einstein-Skyrmion black holes in four dimensions is studied in the extended phase space. We obtain the inversion curves and the isenthalpic curves for different values of parameters K and λ, which represent the coupling strength between the gravity field and matter field. We find that the parameters K and λ have the same effects during the entire Joule-Thomson expansion and the bigger parameter K or λ corresponds to the smaller inversion pressure. Analogously, the phase space {T, P} consist of cooling-heating regions. In addition, the dispersion point of the Joule-Thomson coefficient µ is in correspondence with the zero point of the Hawking temperature T and the ratio of the minimum inversion temperature Tmini and the critical temperature is a constant.","PeriodicalId":9413,"journal":{"name":"Canadian Journal of Physics","volume":"107 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79054638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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