Pub Date : 2018-08-01DOI: 10.22606/ADAP.2018.33006
Foisal B. T. Siddiki, Abdullah Al Mamun, M. Amin
The basic features of linear and nonlinear quantum electron-acoustic (QEA) waves in a degenerate quantum plasma (containing non-relativistically degenerate electrons, superthermal or κ-distributed electrons, and stationary ions) are theoretically investigated. The nonlinear Schödinger (NLS) equation is derived by employing the reductive perturbation method. The stationary solitonic solution of the NLS equation is obtained, and examined analytically as well as numerically to identify the basic features of the QEA envelope solitons. It has been found that the effects of the degeneracy and exchange/Bohm potentials of cold electrons, and superthermality of hot electrons significantly modify the basic properties of linear and nonlinear QEA waves. It is observed that the QEA waves are modulationally unstable for k < kc, where kc is the maximum (critical) value of the QEA wave number k below which the QEA waves are modulationally unstable), and that for k < kc the solution of the NLS equation gives rise to the bright envelope solitons, which are found to be localized in both spatial (ξ) and time (τ) axes. It is also observed that as the spectral index κ is increased, the critical value of the wave number (amplitude of the QEA envelope bright solitons) decreases (increases). The implications of our results should be useful in understanding the localized electrostatic perturbation in solid density plasma produced by irradiating metals by intense laser, semiconductor devices, microelectronics, etc.
{"title":"Quantum Electron-acoustic Envelope Solitons and Their Modulational Instability in a Degenerate Quantum Plasma","authors":"Foisal B. T. Siddiki, Abdullah Al Mamun, M. Amin","doi":"10.22606/ADAP.2018.33006","DOIUrl":"https://doi.org/10.22606/ADAP.2018.33006","url":null,"abstract":"The basic features of linear and nonlinear quantum electron-acoustic (QEA) waves in a degenerate quantum plasma (containing non-relativistically degenerate electrons, superthermal or κ-distributed electrons, and stationary ions) are theoretically investigated. The nonlinear Schödinger (NLS) equation is derived by employing the reductive perturbation method. The stationary solitonic solution of the NLS equation is obtained, and examined analytically as well as numerically to identify the basic features of the QEA envelope solitons. It has been found that the effects of the degeneracy and exchange/Bohm potentials of cold electrons, and superthermality of hot electrons significantly modify the basic properties of linear and nonlinear QEA waves. It is observed that the QEA waves are modulationally unstable for k < kc, where kc is the maximum (critical) value of the QEA wave number k below which the QEA waves are modulationally unstable), and that for k < kc the solution of the NLS equation gives rise to the bright envelope solitons, which are found to be localized in both spatial (ξ) and time (τ) axes. It is also observed that as the spectral index κ is increased, the critical value of the wave number (amplitude of the QEA envelope bright solitons) decreases (increases). The implications of our results should be useful in understanding the localized electrostatic perturbation in solid density plasma produced by irradiating metals by intense laser, semiconductor devices, microelectronics, etc.","PeriodicalId":131060,"journal":{"name":"Advances in Astrophysics","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117181981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.22606/ADAP.2018.33007
H. Fahr, M. Heyl
In two previous papers the authors have investigated the characteristics of freely propagating cosmic photons in expanding homogenous flat universes from particle and wave points of view, respectively. The result was that the energy density of these freely propagating photons scales with 1/S3 instead with the generally accepted and redshift-related 1/S4, with S being the cosmic scale factor. This is a surprising result at first glance but finally very understandable if energy conservation has to be required also for cosmic photons without creating a conflict with observations. In this paper we treat freely propagating cosmic photons with a totally different approach, namely with the electromagnetic energy-momentum tensor (from now on abbreviated with EMT). The implementation of the EMT, when correctly interpreted for freely propagating photons, into Einstein’s field equations then automatically leads to the same 1/S3-scaling law for the energy density of cosmic photons, herewith confirming the results found earlier for the particle and wave view. We conclude that the observed cosmological redshift of photons (energy density ∝ 1/S4) is compatible with the law of energy conservation, i.e energy density ∝ 1/S3 if interpreted on a new physical basis.
{"title":"The Electromagnetic Energy-Momentum Tensor in Expanding Universes","authors":"H. Fahr, M. Heyl","doi":"10.22606/ADAP.2018.33007","DOIUrl":"https://doi.org/10.22606/ADAP.2018.33007","url":null,"abstract":"In two previous papers the authors have investigated the characteristics of freely propagating cosmic photons in expanding homogenous flat universes from particle and wave points of view, respectively. The result was that the energy density of these freely propagating photons scales with 1/S3 instead with the generally accepted and redshift-related 1/S4, with S being the cosmic scale factor. This is a surprising result at first glance but finally very understandable if energy conservation has to be required also for cosmic photons without creating a conflict with observations. In this paper we treat freely propagating cosmic photons with a totally different approach, namely with the electromagnetic energy-momentum tensor (from now on abbreviated with EMT). The implementation of the EMT, when correctly interpreted for freely propagating photons, into Einstein’s field equations then automatically leads to the same 1/S3-scaling law for the energy density of cosmic photons, herewith confirming the results found earlier for the particle and wave view. We conclude that the observed cosmological redshift of photons (energy density ∝ 1/S4) is compatible with the law of energy conservation, i.e energy density ∝ 1/S3 if interpreted on a new physical basis.","PeriodicalId":131060,"journal":{"name":"Advances in Astrophysics","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133867947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.22606/adap.2018.33001
B. Alexeev
The theory of the matter movement in black holes (BH) in the frame of non – local quantum hydrodynamics (NLQHD) is considered. The theory corresponds to the limit case when the matter density tends to infinity when the theory of General Relativity is not applicable in principle. From calculations follow that NLQHD equations for the black holes have the solutions limited in space. The domain of the solution existence is limited by the event horizon where gravity tends to infinity. It was shown: 1) internal perturbations in BH lead to the appearance of the packets of the gravitational waves. 2) The width of the wave packet is inversely proportional to the magnitude of internal energy. 3) Increasing of the internal energy leads to the transformation of the mode of antigravity into the attraction regime. 4) A strong mutual influence of the gravitational, antigravitational and electromagnetic fields exists. The velocity of gravitational waves is more than the speed of light. The numerical calculations of the Cauchy problem are delivered.
{"title":"Application of the Non-Local Physics in the Theory of the Matter Movement in Black Holes","authors":"B. Alexeev","doi":"10.22606/adap.2018.33001","DOIUrl":"https://doi.org/10.22606/adap.2018.33001","url":null,"abstract":"The theory of the matter movement in black holes (BH) in the frame of non – local quantum hydrodynamics (NLQHD) is considered. The theory corresponds to the limit case when the matter density tends to infinity when the theory of General Relativity is not applicable in principle. From calculations follow that NLQHD equations for the black holes have the solutions limited in space. The domain of the solution existence is limited by the event horizon where gravity tends to infinity. It was shown: 1) internal perturbations in BH lead to the appearance of the packets of the gravitational waves. 2) The width of the wave packet is inversely proportional to the magnitude of internal energy. 3) Increasing of the internal energy leads to the transformation of the mode of antigravity into the attraction regime. 4) A strong mutual influence of the gravitational, antigravitational and electromagnetic fields exists. The velocity of gravitational waves is more than the speed of light. The numerical calculations of the Cauchy problem are delivered.","PeriodicalId":131060,"journal":{"name":"Advances in Astrophysics","volume":"221 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132108395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-05-01DOI: 10.22606/ADAP.2019.41001
Michael A. Ivanov
The model of low-energy quantum gravity leads to small additional effects having essential cosmological consequences: redshifts of remote objects and the additional dimming of them may be interpreted without any expansion of the Universe and without dark energy. The theoretical luminosity distance of the model fits the observational Hubble diagrams with high confidence levels. In the model, the ratio H(z)/(1+z) should be equal to the Hubble constant. The constancy of this ratio is confirmed with high probabilities by fitting the compilation of H(z) observations. A deceleration of massive bodies due to forehead and backhead collisions with gravitons is re-computed here.
{"title":"Low-energy Quantum Gravity and Cosmology without Dark Energy","authors":"Michael A. Ivanov","doi":"10.22606/ADAP.2019.41001","DOIUrl":"https://doi.org/10.22606/ADAP.2019.41001","url":null,"abstract":"The model of low-energy quantum gravity leads to small additional effects having essential cosmological consequences: redshifts of remote objects and the additional dimming of them may be interpreted without any expansion of the Universe and without dark energy. The theoretical luminosity distance of the model fits the observational Hubble diagrams with high confidence levels. In the model, the ratio H(z)/(1+z) should be equal to the Hubble constant. The constancy of this ratio is confirmed with high probabilities by fitting the compilation of H(z) observations. A deceleration of massive bodies due to forehead and backhead collisions with gravitons is re-computed here.","PeriodicalId":131060,"journal":{"name":"Advances in Astrophysics","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125050719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-03-04DOI: 10.22606/adap.2018.34005
N. Ahmed, N. A. Chowdhury, A. Mannan, A. Mamun
The existence and the basic features of ion-acoustic (IA) envelope solitons in a self-gravitating degenerate quantum plasma system (SG-DQPS), containing inertial non-relativistically degenerate light and heavy ion species as well as inertialess non-relativistically degenerate positron and electron species, have been theoretically investigated by deriving the nonlinear Schr"{o}dinger (NLS) equation. The NLS equation, which governs the dynamics of the IA waves, has disclosed the modulationally stable and unstable regions for the IA waves. The unstable region allows to generate bright envelope solitons which are modulationaly stable. It is found that the stability and the growth rate dependent on the plasma parameters (like, mass and number density of the plasma species). The implications of our results in astronomical compact object (viz. white dwarfs, neutron stars, and black holes, etc.) are briefly discussed.
{"title":"Self-gravitating Envelope Solitons in a Degenerate Quantum Plasma System","authors":"N. Ahmed, N. A. Chowdhury, A. Mannan, A. Mamun","doi":"10.22606/adap.2018.34005","DOIUrl":"https://doi.org/10.22606/adap.2018.34005","url":null,"abstract":"The existence and the basic features of ion-acoustic (IA) envelope solitons in a self-gravitating degenerate quantum plasma system (SG-DQPS), containing inertial non-relativistically degenerate light and heavy ion species as well as inertialess non-relativistically degenerate positron and electron species, have been theoretically investigated by deriving the nonlinear Schr\"{o}dinger (NLS) equation. The NLS equation, which governs the dynamics of the IA waves, has disclosed the modulationally stable and unstable regions for the IA waves. The unstable region allows to generate bright envelope solitons which are modulationaly stable. It is found that the stability and the growth rate dependent on the plasma parameters (like, mass and number density of the plasma species). The implications of our results in astronomical compact object (viz. white dwarfs, neutron stars, and black holes, etc.) are briefly discussed.","PeriodicalId":131060,"journal":{"name":"Advances in Astrophysics","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127882403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-02-20DOI: 10.22606/adap.2019.43003
L. Barbieri, F. Talamucci
The calculus of apsidal precession frequencies of the planets is developed by means of a perturbation thecnique. A model of concentric rings (ring model), suitable for improving calculations, is introduced. Conclusive remarks concerning a comparison between the theoretical, the calculated and the observed data of the precession frequencies are performed.
{"title":"Calculation of Apsidal Precession via Perturbation Theory","authors":"L. Barbieri, F. Talamucci","doi":"10.22606/adap.2019.43003","DOIUrl":"https://doi.org/10.22606/adap.2019.43003","url":null,"abstract":"The calculus of apsidal precession frequencies of the planets is developed by means of a perturbation thecnique. A model of concentric rings (ring model), suitable for improving calculations, is introduced. Conclusive remarks concerning a comparison between the theoretical, the calculated and the observed data of the precession frequencies are performed.","PeriodicalId":131060,"journal":{"name":"Advances in Astrophysics","volume":"167 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116914078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-02-12DOI: 10.22606/adap.2018.33002
M. Kahil
Equations of spinning objects are obtained in Absolute Parallelism Geometry [AP], a special class of non-Riemannian geometry admitting an alternative non-vanishing curvature and torsion simultaneously. This new set of equations is the counterpart of the Papapetrou equations in the Riemannian geometry. Applying, the concept of geometerization of physics, it may give rise to describe the spin tensor as parameterized commutation relation between path and path deviation equations in both Riemannian and non-Riemannian geometries.
{"title":"The Spinning Equations of Motion for Objects in AP-Geometry","authors":"M. Kahil","doi":"10.22606/adap.2018.33002","DOIUrl":"https://doi.org/10.22606/adap.2018.33002","url":null,"abstract":"Equations of spinning objects are obtained in Absolute Parallelism Geometry [AP], a special class of non-Riemannian geometry admitting an alternative non-vanishing curvature and torsion simultaneously. This new set of equations is the counterpart of the Papapetrou equations in the Riemannian geometry. Applying, the concept of geometerization of physics, it may give rise to describe the spin tensor as parameterized commutation relation between path and path deviation equations in both Riemannian and non-Riemannian geometries.","PeriodicalId":131060,"journal":{"name":"Advances in Astrophysics","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122643546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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