Advanced Studies in Theoretical Physics最新文献

Existence of time-like geodesics in asymptotically flat spacetimes: a generalized topological criterion 渐近平坦时空中类时测地线的存在性:一个广义拓扑判据

Advanced Studies in Theoretical Physics Pub Date : 2023-07-05 DOI: 10.12988/astp.2023.92005

Krish Jhurani, T. McMaken

{"title":"Existence of time-like geodesics in asymptotically flat spacetimes: a generalized topological criterion","authors":"Krish Jhurani, T. McMaken","doi":"10.12988/astp.2023.92005","DOIUrl":"https://doi.org/10.12988/astp.2023.92005","url":null,"abstract":"This paper examines the issue of the existence and nature of time-like geodesics in asymptotically flat spacetimes and proposes a novel generalized topological criterion for the existence of time-like geodesics. Its validity is proved using theorems such as the Jordan-Brouwer Separation Theorem, the Raychaudhuri Equation, and key elements of Differential Geometry. More specifically, the proof primarily hinges on a closed, simply-connected subset of the spacetime manifold and a continuous map, causing a non-trivial induction on the first homology groups, from the boundary of this subset to a unit circle. The mathematical analysis conclusively affirms the presence of these geodesics, intersecting transversally within the said subset of spacetime. Findings underscore these geodesics' significant implications for the structure of asymptotically flat spacetimes, including stability, and hypothetical existence of wormholes. The generalized topological criterion also has implications on the problem of obstructions for the existence of Lorentzian metrics, and Einstein's Constraint Equations. Future research should extend this topological criterion to other classes of spacetimes, including those with non-trivial topologies or non-zero cosmological constants. Also, the criterion's application to study complex dynamical systems, such as gravitational waves or rotating black holes, could offer significant insights.","PeriodicalId":127314,"journal":{"name":"Advanced Studies in Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133426667","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}

引用次数: 0

Simplifying astronomy via Mach's principle, Einstein's equivalence principle, and the gravity-phase-shift 通过马赫原理、爱因斯坦等效原理和引力相移简化天文学

Advanced Studies in Theoretical Physics Pub Date : 2023-01-01 DOI: 10.12988/astp.2023.92008

Riadh Al Rabeh

{"title":"Simplifying astronomy via Mach's principle, Einstein's equivalence principle, and the gravity-phase-shift","authors":"Riadh Al Rabeh","doi":"10.12988/astp.2023.92008","DOIUrl":"https://doi.org/10.12988/astp.2023.92008","url":null,"abstract":"Present day astronomy is highly complex and multi-disciplinary. It relies on the presumed existence of dark matter, dark energy, expanding universe, a big bang starting point, and many singularity blackholes dotted in the picture. We propose to simplify this using Mach’s principle of the effect of distant masses, Einstein equivalence and gravity phase-shit idea, and the author’s idea regarding the radiation origin of matter [1]. We only use simple and well-known facts to do this. The effect of distant masses solves the problem of terminal rotation curves in galaxies. Dark matter and dark energy problems are explained via Einstein equivalence principle and the gravity phase-shift, and the radiation origin of matter is used to understand the nature of stars and blackholes excluding any singularity solution. The universe is perceived as an eternal dynamic structure, ruled by familiar forces and concepts in which the gravity can cause limitless mass accumulation to form stars that subsequently and a result of external and internal factors, disintegrate and eject some or all of their accumulated matter. In the process we obtain formulae for calculating Newton’s universal constant of gravitation, the condition for forming a blackhole, the pressure level inside stars, a formula for the Hubble constant via gravitational redshift, and a formula for the terminal condition of the rotation curves of galaxies-helped by Mach’s principle regarding the effect of distant masses. We also point to supporting statements to our results in published literature.","PeriodicalId":127314,"journal":{"name":"Advanced Studies in Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135550665","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}

引用次数: 0

From vacuum to dark energy. Exact anisotropic cosmological solution of Petrov type D for a nonlinear scalar field 从真空到暗能量。非线性标量场的Petrov型D的精确各向异性宇宙学解

Advanced Studies in Theoretical Physics Pub Date : 2023-01-01 DOI: 10.12988/astp.2023.92010

R. Alvarado

{"title":"From vacuum to dark energy. Exact anisotropic cosmological solution of Petrov type D for a nonlinear scalar field","authors":"R. Alvarado","doi":"10.12988/astp.2023.92010","DOIUrl":"https://doi.org/10.12988/astp.2023.92010","url":null,"abstract":"Two exact solutions to Einstein equations, which diﬀer because of its type of initial expansion, are obtained to a nonlinear scalar ﬁeld with a potential type V = Λ (cid:16) 1 − tanh ( √ 6 φ 2 ) 4 (cid:17) . It is determined that the energy density of solutions is not singular for any time value and for which at the beginning in t = 0, the space-time is a vacuum of Kasner type ( a 1 = a 2 = − 2 a 3 = 2 / 3) for one solution and the ﬂat world for the other. By having studied the temperature, it is established that it is null at the beginning and that once it increases up to a maximum value, it stops increases and asymptotically goes down to zero in respect to time. The Hubble and deceleration parameters were studied, it is showed that the Hubble parameter is indeﬁnite in t = 0 and tends to have a constant value as time increases; then, the deceleration parameter indicates an initial process of a decelerated expansion that continuously changes into an accelerated one as time increases. By the study of the Jacobi stability of the solutions, it is obtained that the solutions are initially unstability but cease to be so in a determined time. The space-time of both solutions transforms into the equivalent of dark energy for FRWL as time increases.","PeriodicalId":127314,"journal":{"name":"Advanced Studies in Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136207546","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}

引用次数: 0

Anisotropic cosmological exact solutions of Petrov type D of a mixture of dark energy and an attractive Bose-Einstein condensate 暗能量和吸引玻色-爱因斯坦凝聚物混合的Petrov型D的各向异性宇宙学精确解

Advanced Studies in Theoretical Physics Pub Date : 2023-01-01 DOI: 10.12988/astp.2023.92009

R. Alvarado

{"title":"Anisotropic cosmological exact solutions of Petrov type D of a mixture of dark energy and an attractive Bose-Einstein condensate","authors":"R. Alvarado","doi":"10.12988/astp.2023.92009","DOIUrl":"https://doi.org/10.12988/astp.2023.92009","url":null,"abstract":"Two exact solutions to Einstein equations were obtained; whose difference is the kind of initial expansion (greater on an axis or on a plane) in an anisotropic and homogeneous symmetry of Petrov type D. In these solutions, a mixture of dark energy and a ”standard” attractive Bose-Einstein Condensate (BEC) were considered. The initial singularity problem was studied and is only present in one of these models. Also, the study of temperature allowed to determine that it is null at the start of the universe and as time increases asymptotically, it tends to a constant value, hence a BEC is essential in the ﬁrst expansion phase and, for this work, with 8 / 9 parts of the total early universe energy. Hubble and deceleration parameters were studied as well and it was determined that the Hubble parameter initially gets indeﬁnite in t = 0, but tends to a constant value when time increases; for the deceleration parameter, it was stated that the universe initially expands in a decelerated form, but from a certain value, it starts continuously to expand fast towards a constant value. As time increases asymptotically, models tend to a one of FRWL ﬂat type of dark energy.","PeriodicalId":127314,"journal":{"name":"Advanced Studies in Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136207551","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}

引用次数: 0

Evaluation of cross section of elastic scattering for non-relativistic and relativistic particles by means of fundamental scattering formulas 用基本散射公式计算非相对论性和相对论性粒子的弹性散射截面

Advanced Studies in Theoretical Physics Pub Date : 2022-07-17 DOI: 10.12988/astp.2022.91866

Huailong Wang

引用次数: 2

Scale invariance and dilaton mass 尺度不变性和膨胀质量

Advanced Studies in Theoretical Physics Pub Date : 2021-10-28 DOI: 10.12988/astp.2022.91844

I. Oda

引用次数: 0

Considering Measurement Dynamics In Classical Mechanics Considering经典力学中的测量动力学

Advanced Studies in Theoretical Physics Pub Date : 2021-04-29 DOI: 10.21203/RS.3.RS-475105/V1

N. Matjelo

引用次数: 0

Spontaneous symmetry breakdown of scale symmetries 尺度对称的自发对称分解

Advanced Studies in Theoretical Physics Pub Date : 2020-03-17 DOI: 10.12988/astp.2020.91464

I. Oda

引用次数: 3

Emergence of Einstein gravity from Weyl gravity 爱因斯坦引力从Weyl引力中出现

Advanced Studies in Theoretical Physics Pub Date : 2020-03-03 DOI: 10.12988/astp.2021.91707

I. Oda

引用次数: 7

The Einstein dual theory of relativity 爱因斯坦相对论的对偶理论

Advanced Studies in Theoretical Physics Pub Date : 2020-01-30 DOI: 10.12988/astp.2019.9312

T. Gill, G. A. D. Parga

{"title":"The Einstein dual theory of relativity","authors":"T. Gill, G. A. D. Parga","doi":"10.12988/astp.2019.9312","DOIUrl":"https://doi.org/10.12988/astp.2019.9312","url":null,"abstract":"{This paper is a comparison of the Minkowski, Einstein and Einstein dual theories of relativity. The dual is based on an identity relating the observer time and the proper time as a contact transformation on configuration space, which leaves phase space invariant. The theory is dual in that, for a system of $n$ particles, any inertial observer has two unique sets of global variables $({bf{X}}, t)$ and $({bf{X}}, tau)$ to describe the dynamics. Where ${bf{X}}$ is the (unique) canonical center of mass. In the $({bf{X}}, t)$ variables, time is relative and the speed of light is unique, while in the $({bf{X}}, tau)$ variables, time is unique and the speed of light is relative with no upper bound. The two sets of particle and Maxwell field equations are mathematically equivalent, but the particle wave equations are not. The dual version contains an additional longitudinal radiation term that appears instantaneously with acceleration, does not depend on the nature of the force and the Wheeler-Feynman absorption hypothesis is a corollary. \u0000The homogenous and isotropic nature of the universe is sufficient to prove that a unique definition of Newtonian time exists with zero set at the big bang. The isotopic dual of $R$ is used to improve the big bang model, by providing an explanation for the lack of antimatter in our universe, a natural arrow for time, conservation of energy, momentum and angular momentum. This also solves the flatness and horizon problems without inflation. \u0000We predict that radiation from a betatron (of any frequency) will not produce photoelectrons, that matter and antimatter are gravitationally repulsive and that data from distant sources does not have a unique physical interpretation. We provide a table showing the differences between the Minkowski, Einstein and dual versions of the special theory.}","PeriodicalId":127314,"journal":{"name":"Advanced Studies in Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133398922","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}

引用次数: 2