Abstract:
We apply the spacetime dependent lagrangian formalism [1] to the action in general relativity. We obtain a Barriola-Vilenkin type monopole solution by exploiting theelectrogravity duality of the vacuum Einstein equations and using a modified definition of empty space. An {\it upper bound} is obtained on the monopole mass ${\tt M}$, ${\tt M}\leq e^{(1-\alpha)/\alpha}/(1-\alpha)^{2}{\tt G}$ where $\alpha = 2k $ is the global monopole charge. Keywords: global monopole, electrogravity duality, holographic principle. PACS: 11.15.-q, 11.27.+d, 14.80.Hv, 04.

Abstract:
The quantum tunneling framework is adopted to investigate tunneling radiation of Barriola-Vilenkin black hole with a global monopole. We obtain a conclusion that the emission rate of massive particles is related with the change of Bekenstein-Hawking entropy. The emission rates of massless and massive particles take the same functional form. It is consistent with the underlying unitary theory.

Abstract:
The well known monopole solution of Barriola and Vilenkin (BV) resulting from the breaking of a global SO(3) symmetry is extended in general relativity along with a zero mass scalar field and also in Brans-Dicke(BD) theory of gravity.In the case of BD theory, the behaviour of spacetime and other variables such as BD scalar field and the monopole energy density have been studied numerically.For monopole along with a zero mass scalar field, exact solutions are obtained and depending upon the choice of arbitary parameters, the solutions either reduce to the BV case or to a pure scalar field solution as special cases.It is interesting to note that unlike the BV case the global monopole in the BD theory does exert gravitational pull on a test particle moving in its spacetime.

Abstract:
The partition functions of bosonic and fermionic field in Barriola_Vilenkin black hole are directly derived by using the method of quantum statistics. Then the entropy of the Barriola_Vilenkin black hole is calculated by using the improved brick_wall method in the frame of membrane model.

Abstract:
Using the thin film model of black hole, the thermal radiation laws of the Barriola-Vilenkin black hole are studied. We obtained the result that the thermal radiation of the black hole always satisfies the generalized Stenfan-Boltzmann law. The derived generalized Stenfan-Boltzmann coefficient is no longer a constant. When the cut-off distance and the thin film thickness are both fixed, it is a proportional coefficient related to the space-time metric near the event horizon and the average radial effusion velocity of the radiation particles in the thin film. The radiation energy flux of the Dirac field of the Barriola-Vilenkin black hole is proportional to the average radial effusion velocity of the radiation particles in the thin film, and inversely proportional to the square of the black hole mass.

Abstract:
The quantum corrections to the entropy of the Barriola-Vilenkin black hole due to the gravitation electromagnetic and neutrino fields are calculated by using the brick-wall model. It is shown that the quantum corrects consist in two parts: One is aquadratic divergent term at event horizon and is proportional to the surface area of the event horizon. The other is two logarithmically divergent terms which not only depend on the characteristics of the black hole but also on the spin of fields. The whole expression does not take the form of the scalar field.

Abstract:
The quantum corrections to the entropy of the Barriola-Vilenkin black hole due to the massless gravitational field are calculated by using the brick-wall model.It is shown that the quantum corrections consist of two parts:One is a quadratic divergent term at the event horizon and is proportional to the surface area of the event horizon.The other is two logarithmically divergent terms which not only depend on the characteristics of the black hole but also on the spin of the field.The whole expression does not take the form of the scalar field.

Abstract:
We define spacetimes that are asymptotically flat, except for a deficit solid angle $\alpha$, and present a definition of their ``ADM'' mass, which is finite for this class of spacetimes, and, in particular, coincides with the value of the parameter $M$ of the global monopole spacetime studied by Vilenkin and Barriola . Moreover, we show that the definition is coordinate independent, and explain why it can, in some cases, be negative.

Abstract:
in this paper we review some important aspects of the global monopole spacetime and present how this manifold modifies, at classical and quantum points of view, the movement of a charged particle. the explicit calculations of the renormalized vacuum expectation values of the energy-momentum tensors, átmn(x)？ren., associated with massless bosonic and fermionic fields are also presented. moreover the effect of the nonzero temperature in this previous formalism is analyzed. finally, we briefly present other applications of this manifold in the topological inflation and condensed matter system.

Abstract:
In this paper we review some important aspects of the global monopole spacetime and present how this manifold modifies, at classical and quantum points of view, the movement of a charged particle. The explicit calculations of the renormalized vacuum expectation values of the energy-momentum tensors, áTmn(x) Ren., associated with massless bosonic and fermionic fields are also presented. Moreover the effect of the nonzero temperature in this previous formalism is analyzed. Finally, we briefly present other applications of this manifold in the topological inflation and condensed matter system.