Recently Malihe Heydari-Fard obtained a spherically symmetric exterior black hole solution in the brane-world scenario, which can be used to explain the galaxy rotation curves without postulating dark matter. By analy...Recently Malihe Heydari-Fard obtained a spherically symmetric exterior black hole solution in the brane-world scenario, which can be used to explain the galaxy rotation curves without postulating dark matter. By analysing the particle effective potential, we have investigated the time-like geodesic structure of the spherically symmetric black hole in the brane-world. We mainly take account of how the cosmological constant α and the stellar pressure β affect the time-like geodesic structure of the black hole. We find that the radial particle falls to the singularity from a finite distance or plunges into the singularity, depending on its initial conditions. But the non-radial time-like geodesic structure is more complex than the radial case. We find that the particle moves on the bound orbit or stable （unstable） circle orbit or plunges into the singularity, or reflects to infinity, depending on its energy and initial conditions. By comparing the particle effective potential curves for different values of the stellar pressureβ and the cosmological constant α, we find that the stellar pressure parameter β does not affect the time-like geodesic structure of the black hole, but the cosmological constant a has an impact on its time-like geodesic structure.展开更多
In this paper, infinitesimal deformations of time-like surfaces are investigated in Minkowski 3-space R2,1. It is shown that some given deformations of the time-like surface can be described by 2+1 dimensional integra...In this paper, infinitesimal deformations of time-like surfaces are investigated in Minkowski 3-space R2,1. It is shown that some given deformations of the time-like surface can be described by 2+1 dimensional integrable systems. Moreover spectral parameters are introduced, and it is proved that deformation families are soliton surfaces’ families.展开更多
In this paper we investigate the influence of the dark energy on the time-like geodesic motion of a particle in Schwarzschild spacetime by analysing the behaviour of the effective potential which appears in an equatio...In this paper we investigate the influence of the dark energy on the time-like geodesic motion of a particle in Schwarzschild spacetime by analysing the behaviour of the effective potential which appears in an equation of motion. For the non-radial time-like geodesics, we find a bound orbit when the particle energy is in an appropriate range, and also find another possible orbit, which is that the particle drops straightly into the singularity of a black hole or escapes to infinity. For the radial time-like geodesics, we find an unstable circular orbit when the particle energy is the critical value, in which case it is possible for the particle to escape to infinity.展开更多
A hypersurface x(M)in Lorentzian space R41 is called conformal homogeneous,if for any two points p,q on M,there exists,a conformal transformation of R41,such that(x(M))=x(M),(x(p))=x(q).In this paper,the authors gi...A hypersurface x(M)in Lorentzian space R41 is called conformal homogeneous,if for any two points p,q on M,there exists,a conformal transformation of R41,such that(x(M))=x(M),(x(p))=x(q).In this paper,the authors give a complete classifica-tion for regular time-like conformal homogeneous hypersurfaces in R41 with three distinct principal curvatures.展开更多
By using dressing actions of the Gn-1,n-1^1,1-system,the authors study geometric transformations for flat time-like n-submanifolds with flat,non-degenerate normal bundle in anti-de Sitter space H1^2n-1(-1),where Gn-1,...By using dressing actions of the Gn-1,n-1^1,1-system,the authors study geometric transformations for flat time-like n-submanifolds with flat,non-degenerate normal bundle in anti-de Sitter space H1^2n-1(-1),where Gn-1,n-1^1,1=0（2n-2,2/O(n-1,1)×O(n-1,1).展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 10873004)the Program for Excellent Talents in Hunan Normal University (Grant No. ET10803)+3 种基金the State Key Development Program for Basic Research Project of China(Grant No. 2010CB832803)the Key Project of the National Natural Science Foundation of China (Grant No. 10935013)the Constructing Program of the National Key Disciplinethe Program for Changjiang Scholars and Innovative Research Teamin University (Grant No. IRT0964)
文摘Recently Malihe Heydari-Fard obtained a spherically symmetric exterior black hole solution in the brane-world scenario, which can be used to explain the galaxy rotation curves without postulating dark matter. By analysing the particle effective potential, we have investigated the time-like geodesic structure of the spherically symmetric black hole in the brane-world. We mainly take account of how the cosmological constant α and the stellar pressure β affect the time-like geodesic structure of the black hole. We find that the radial particle falls to the singularity from a finite distance or plunges into the singularity, depending on its initial conditions. But the non-radial time-like geodesic structure is more complex than the radial case. We find that the particle moves on the bound orbit or stable （unstable） circle orbit or plunges into the singularity, or reflects to infinity, depending on its energy and initial conditions. By comparing the particle effective potential curves for different values of the stellar pressureβ and the cosmological constant α, we find that the stellar pressure parameter β does not affect the time-like geodesic structure of the black hole, but the cosmological constant a has an impact on its time-like geodesic structure.
基金This work was supported by NSFC(10301030) and 973 project, "nonlinear
文摘In this paper, infinitesimal deformations of time-like surfaces are investigated in Minkowski 3-space R2,1. It is shown that some given deformations of the time-like surface can be described by 2+1 dimensional integrable systems. Moreover spectral parameters are introduced, and it is proved that deformation families are soliton surfaces’ families.
基金Project supported by the State Key Development Program for Basic Research Program of China (Grant No 2003CB716300)the National Natural Science Foundation of China (Grant No 10547114)
文摘In this paper we investigate the influence of the dark energy on the time-like geodesic motion of a particle in Schwarzschild spacetime by analysing the behaviour of the effective potential which appears in an equation of motion. For the non-radial time-like geodesics, we find a bound orbit when the particle energy is in an appropriate range, and also find another possible orbit, which is that the particle drops straightly into the singularity of a black hole or escapes to infinity. For the radial time-like geodesics, we find an unstable circular orbit when the particle energy is the critical value, in which case it is possible for the particle to escape to infinity.
基金supported by the Principal’s Fund(No.KJ2020002)the second is supported by the National Natural Science Foundation of China(Nos.11671330 and 11871405)the third is supported by the National Natural Science Foundation of China(Nos.11831005,1196131001).
文摘A hypersurface x(M)in Lorentzian space R41 is called conformal homogeneous,if for any two points p,q on M,there exists,a conformal transformation of R41,such that(x(M))=x(M),(x(p))=x(q).In this paper,the authors give a complete classifica-tion for regular time-like conformal homogeneous hypersurfaces in R41 with three distinct principal curvatures.
基金Project supported supported by the 973 Project of the Ministry of Science and Technology of Chinathe National Natural Science Foundation of China (No. 10301030).
文摘By using dressing actions of the Gn-1,n-1^1,1-system,the authors study geometric transformations for flat time-like n-submanifolds with flat,non-degenerate normal bundle in anti-de Sitter space H1^2n-1(-1),where Gn-1,n-1^1,1=0（2n-2,2/O(n-1,1)×O(n-1,1).
