In this work we present a study of a new method to prove the equation of the gravitational red shift of spec-tral lines. That’s according to the generalized special relativity theory. The equation of the gravitationa...In this work we present a study of a new method to prove the equation of the gravitational red shift of spec-tral lines. That’s according to the generalized special relativity theory. The equation of the gravitational red shift of spectral lines has been studied in many different works, using different methods depending on the Newtonian mechanics, and other theories. Although attention was drawn to the fact that the well-known ex-pression of the gravitational Red-Shift of spectral lines may be derived with no recourse to the general rela-tivity theory! In this study a unique derivation has been done using the Generalized Special Relativity (GSR) and the same result obtained.展开更多
The post-Newtonian scheme in multiple systems with post-Newtonian parameters presented by Klioner and Soffel is extended to the post-post-Newtonian （PPN） order for light propagation problem in the solar system. Unde...The post-Newtonian scheme in multiple systems with post-Newtonian parameters presented by Klioner and Soffel is extended to the post-post-Newtonian （PPN） order for light propagation problem in the solar system. Under considering the solar system experiment requirement, a new parameter ε is introduced. This extension does not change the virtue of the scheme on the linear partial differential equations of the potential and vector potential mentioned in previous work. Furthermore, this extension is based on the former work done by Richter and Matzner in one global system theory. As an application, we also consider the deflection of light ray in the global coordinates. And the deflection angle of light ray is obtained with post-Newtonian parameters.展开更多
We present a new numerical method to approximate the solutions of an Euler-Poisson model,which is inherent to astrophysical flows where gravity plays an important role.We propose a discretization of gravity which ensu...We present a new numerical method to approximate the solutions of an Euler-Poisson model,which is inherent to astrophysical flows where gravity plays an important role.We propose a discretization of gravity which ensures adequate coupling of the Poisson and Euler equations,paying particular attention to the gravity source term involved in the latter equations.In order to approximate this source term,its discretization is introduced into the approximate Riemann solver used for the Euler equations.A relaxation scheme is involved and its robustness is established.The method has been implemented in the software HERACLES[29]and several numerical experiments involving gravitational flows for astrophysics highlight the scheme.展开更多
Some future space missions measure distances of laser links and angles with unprecedented precision,allowing us to test theories of gravity up to the two-post-Newtonian(2PN)order.Besides,investigation of an intermedia...Some future space missions measure distances of laser links and angles with unprecedented precision,allowing us to test theories of gravity up to the two-post-Newtonian(2PN)order.Besides,investigation of an intermediate-range force has been of considerable interests in gravitational experiments.Inspired by these ideas,within the framework of the scalar-tensor theory with an intermediaterange force,its 2PN approximation is obtained with Chandrasekhar’s approach.It includes the 2PN metric and equations of motion for general matter without specific equation of state.The conserved quantities to the 2PN order are isolated with the aid of the energy-momentum complex.We also discuss the prospect of testing and distinguishing the intermediate-range force with the orbital motions of celestial bodies and spacecrafts.展开更多
THE theory of unified representation of gravitation field proposed by the author is modelledupon spherical approximation for disturbing potential. It is a common knowledge that sphericalapproximation should lead to a ...THE theory of unified representation of gravitation field proposed by the author is modelledupon spherical approximation for disturbing potential. It is a common knowledge that sphericalapproximation should lead to a result involving an innate error. This kind of error is tolerableonly for general application, an ellipsoidal correction has to be taken into account in case of de-siring for a result with higher accuracy. The purpose of this note is to try to make an展开更多
Recently proposed two swampland criteria that arising from string theory landscape leads to the important challenge of the realization of single-field inflationary models. Especially one of swampland criteria which im...Recently proposed two swampland criteria that arising from string theory landscape leads to the important challenge of the realization of single-field inflationary models. Especially one of swampland criteria which implies a large tensor-to-scalar ratio is strongly in tension with recent observational results. In this paper, we explore the possibility the swampland conjectures could be compatible with single-field inflationary scenarios if the effects due to the quantum theory of gravity are considered. We show that the quantum gravitational effects due to the nonlinear dispersion relation provides significant modifications on the amplitude of both the scalar and tensor perturbation spectra. Such modifications could be either raise or reduce the perturbation spectra depending on the values of the parameters in the nonlinear terms of the dispersion relations. Therefore, these effects can reduce the tensor-to-scalar ratio to a smaller value, which helps to relax the tension between the swampland conjecture and observational data.展开更多
文摘In this work we present a study of a new method to prove the equation of the gravitational red shift of spec-tral lines. That’s according to the generalized special relativity theory. The equation of the gravitational red shift of spectral lines has been studied in many different works, using different methods depending on the Newtonian mechanics, and other theories. Although attention was drawn to the fact that the well-known ex-pression of the gravitational Red-Shift of spectral lines may be derived with no recourse to the general rela-tivity theory! In this study a unique derivation has been done using the Generalized Special Relativity (GSR) and the same result obtained.
基金supported by the National Natural Science Foundation of China (Grant No. 10674099)the National Science Foundation for Young Scientists of China (Grant No. 10925313)the Shandong Provincial Natural Science Foundation,China (GrantNo. ZR2010AQ023)
文摘The post-Newtonian scheme in multiple systems with post-Newtonian parameters presented by Klioner and Soffel is extended to the post-post-Newtonian （PPN） order for light propagation problem in the solar system. Under considering the solar system experiment requirement, a new parameter ε is introduced. This extension does not change the virtue of the scheme on the linear partial differential equations of the potential and vector potential mentioned in previous work. Furthermore, this extension is based on the former work done by Richter and Matzner in one global system theory. As an application, we also consider the deflection of light ray in the global coordinates. And the deflection angle of light ray is obtained with post-Newtonian parameters.
基金supported by the A.N.R.(Agence Nationale de la Recherche)through the projects SiNeRGHY(ANR-06-CIS6-009-01)and Anemos(ANR-11-MONU002).
文摘We present a new numerical method to approximate the solutions of an Euler-Poisson model,which is inherent to astrophysical flows where gravity plays an important role.We propose a discretization of gravity which ensures adequate coupling of the Poisson and Euler equations,paying particular attention to the gravity source term involved in the latter equations.In order to approximate this source term,its discretization is introduced into the approximate Riemann solver used for the Euler equations.A relaxation scheme is involved and its robustness is established.The method has been implemented in the software HERACLES[29]and several numerical experiments involving gravitational flows for astrophysics highlight the scheme.
基金supported by the National Natural Science Foundation of China(Grant Nos.11473072 and 11103085)the Fundamental Research Program of Jiangsu Province of China(Grant No.BK20131461)
文摘Some future space missions measure distances of laser links and angles with unprecedented precision,allowing us to test theories of gravity up to the two-post-Newtonian(2PN)order.Besides,investigation of an intermediate-range force has been of considerable interests in gravitational experiments.Inspired by these ideas,within the framework of the scalar-tensor theory with an intermediaterange force,its 2PN approximation is obtained with Chandrasekhar’s approach.It includes the 2PN metric and equations of motion for general matter without specific equation of state.The conserved quantities to the 2PN order are isolated with the aid of the energy-momentum complex.We also discuss the prospect of testing and distinguishing the intermediate-range force with the orbital motions of celestial bodies and spacecrafts.
文摘THE theory of unified representation of gravitation field proposed by the author is modelledupon spherical approximation for disturbing potential. It is a common knowledge that sphericalapproximation should lead to a result involving an innate error. This kind of error is tolerableonly for general application, an ellipsoidal correction has to be taken into account in case of de-siring for a result with higher accuracy. The purpose of this note is to try to make an
基金Supported by National Natural Science Foundation of China under Grant No.11675143the Fundamental Research for the Provincial Universities of Zhejiang in China under Grant No.RF-A2019015
文摘Recently proposed two swampland criteria that arising from string theory landscape leads to the important challenge of the realization of single-field inflationary models. Especially one of swampland criteria which implies a large tensor-to-scalar ratio is strongly in tension with recent observational results. In this paper, we explore the possibility the swampland conjectures could be compatible with single-field inflationary scenarios if the effects due to the quantum theory of gravity are considered. We show that the quantum gravitational effects due to the nonlinear dispersion relation provides significant modifications on the amplitude of both the scalar and tensor perturbation spectra. Such modifications could be either raise or reduce the perturbation spectra depending on the values of the parameters in the nonlinear terms of the dispersion relations. Therefore, these effects can reduce the tensor-to-scalar ratio to a smaller value, which helps to relax the tension between the swampland conjecture and observational data.
