In this paper, we study existence and uniqueness of solutions to nonlinear three point boundary value problems for fractional differential equation of the type c D δ 0+ u(t) = f (t, u(t), c D σ 0+ u(t)), t...In this paper, we study existence and uniqueness of solutions to nonlinear three point boundary value problems for fractional differential equation of the type c D δ 0+ u(t) = f (t, u(t), c D σ 0+ u(t)), t ∈ [0, T ], u(0) = αu(η), u(T ) = βu(η), where 1 〈 δ 〈 2, 0 〈 σ 〈 1, α, β∈ R, η∈ (0, T ), αη(1 -β) + (1-α)(T βη) = 0 and c D δ 0+ , c D σ 0+ are the Caputo fractional derivatives. We use Schauder fixed point theorem and contraction mapping principle to obtain existence and uniqueness results. Examples are also included to show the applicability of our results.展开更多
It is shown that the differential form of Friedmann equations of Friedman-Robertson-Walker (FRW) universe can be recast as a similar form of the first law ThdSh = dE+ WdV of thermodynamics at the apparent horizon o...It is shown that the differential form of Friedmann equations of Friedman-Robertson-Walker (FRW) universe can be recast as a similar form of the first law ThdSh = dE+ WdV of thermodynamics at the apparent horizon of FRW universe filled with the viscous fluid. It is also shown that by employing the general expression of temperature Th=|k|/2π=1/2π~rA(1-2~rA/2H^rA)associated with the apparent horizon of an FRW universe and assumed that the temperature Tm of the energy inside the apparent horizon is proportional to the horizon temperature Tm=bTh, we are able to show that the generalized second law of thermodynamics holds in the Einstein gravity provided Th-Tm/~rA≤(ρ+~P).展开更多
There has been lots of interest in exploring the thermodynamic properties at the horizon of a black hole spacetime.It has been shown earlier that for different spacetimes,the Einstein field equations at the horizon ca...There has been lots of interest in exploring the thermodynamic properties at the horizon of a black hole spacetime.It has been shown earlier that for different spacetimes,the Einstein field equations at the horizon can be expressed as the first law of black hole thermodynamics.Using the idea of foliation,we develop a simpler procedure toobtain such results.We considerγ=constant slices,for the Schwarzschild and Reissner-Nordstrom black hole spacetimes.The Einstein field equations for the induced 3-dimensional metrics of the hypersurfaces are expressed in thermodynamic quantities under the virtual displacements of the hypersurfaces.As expected,it is found that the field equations of the induced metric corresponding to the horizon can be written as afirst law of black hole thermodynamics.It is to be mentioned here that our procedure is much easier,to obtain such results,as here one has to essentially deal with(n-1)-dimensional induced metric for an n-dimensional spacetime.展开更多
It has been shown [Chin. Phys. Lett.25 (2008) 4199] that the generalized second law of thermodynamics holds in Einstein gravity. Here we extend this procedure for Gauss-Bonnet and Lovelock gravities. It is shown tha...It has been shown [Chin. Phys. Lett.25 (2008) 4199] that the generalized second law of thermodynamics holds in Einstein gravity. Here we extend this procedure for Gauss-Bonnet and Lovelock gravities. It is shown that by employing the general expression for temperature Th =|κ|/2π= 1/2πτA (1-τA/2HτA) associated with the apparent horizon of a Friedman Robertson-Walker (FRW) universe and assuming Tm = bTh, we are able to construct conditions for which the generalized second law holds in Gauss Bonnet and Lovelock gravities, where Tm and Th are the temperatures of the source and the horizon respectively.展开更多
In this paper, we are dealing with the study of the metric dimension of some classes of regular graphs by considering a class of bridgeless cubic graphs called the flower snarks Jn, a class of cubic convex polytopes c...In this paper, we are dealing with the study of the metric dimension of some classes of regular graphs by considering a class of bridgeless cubic graphs called the flower snarks Jn, a class of cubic convex polytopes considering the open problem raised in [M. Imran et al., families of plane graphs with constant metric dimension, Utilitas Math., in press] and finally Harary graphs H5,n by partially answering to an open problem proposed in Ⅱ. Javaid et al., Families of regular graphs with constant metric dimension, Utilitas Math., 2012, 88: 43-57]. We prove that these classes of regular graphs have constant metric dimension.展开更多
We construct various cases for validity of the generalized second law(GSL)of thermodynamics by assuming the logarithmic correction to the horizon entropy of an evolving wormhole.It is shown that the GSL is always resp...We construct various cases for validity of the generalized second law(GSL)of thermodynamics by assuming the logarithmic correction to the horizon entropy of an evolving wormhole.It is shown that the GSL is always respected forα0≤0,whereas forα0>0 the GSL is respected only ifπr2A+/ℏ<α.展开更多
文摘In this paper, we study existence and uniqueness of solutions to nonlinear three point boundary value problems for fractional differential equation of the type c D δ 0+ u(t) = f (t, u(t), c D σ 0+ u(t)), t ∈ [0, T ], u(0) = αu(η), u(T ) = βu(η), where 1 〈 δ 〈 2, 0 〈 σ 〈 1, α, β∈ R, η∈ (0, T ), αη(1 -β) + (1-α)(T βη) = 0 and c D δ 0+ , c D σ 0+ are the Caputo fractional derivatives. We use Schauder fixed point theorem and contraction mapping principle to obtain existence and uniqueness results. Examples are also included to show the applicability of our results.
文摘It is shown that the differential form of Friedmann equations of Friedman-Robertson-Walker (FRW) universe can be recast as a similar form of the first law ThdSh = dE+ WdV of thermodynamics at the apparent horizon of FRW universe filled with the viscous fluid. It is also shown that by employing the general expression of temperature Th=|k|/2π=1/2π~rA(1-2~rA/2H^rA)associated with the apparent horizon of an FRW universe and assumed that the temperature Tm of the energy inside the apparent horizon is proportional to the horizon temperature Tm=bTh, we are able to show that the generalized second law of thermodynamics holds in the Einstein gravity provided Th-Tm/~rA≤(ρ+~P).
文摘There has been lots of interest in exploring the thermodynamic properties at the horizon of a black hole spacetime.It has been shown earlier that for different spacetimes,the Einstein field equations at the horizon can be expressed as the first law of black hole thermodynamics.Using the idea of foliation,we develop a simpler procedure toobtain such results.We considerγ=constant slices,for the Schwarzschild and Reissner-Nordstrom black hole spacetimes.The Einstein field equations for the induced 3-dimensional metrics of the hypersurfaces are expressed in thermodynamic quantities under the virtual displacements of the hypersurfaces.As expected,it is found that the field equations of the induced metric corresponding to the horizon can be written as afirst law of black hole thermodynamics.It is to be mentioned here that our procedure is much easier,to obtain such results,as here one has to essentially deal with(n-1)-dimensional induced metric for an n-dimensional spacetime.
文摘It has been shown [Chin. Phys. Lett.25 (2008) 4199] that the generalized second law of thermodynamics holds in Einstein gravity. Here we extend this procedure for Gauss-Bonnet and Lovelock gravities. It is shown that by employing the general expression for temperature Th =|κ|/2π= 1/2πτA (1-τA/2HτA) associated with the apparent horizon of a Friedman Robertson-Walker (FRW) universe and assuming Tm = bTh, we are able to construct conditions for which the generalized second law holds in Gauss Bonnet and Lovelock gravities, where Tm and Th are the temperatures of the source and the horizon respectively.
基金supported by National University of Sceinces and Technology (NUST),Islamabadgrant of Higher Education Commission of Pakistan Ref.No:PMIPFP/HRD/HEC/2011/3386support of Slovak VEGA Grant 1/0130/12
文摘In this paper, we are dealing with the study of the metric dimension of some classes of regular graphs by considering a class of bridgeless cubic graphs called the flower snarks Jn, a class of cubic convex polytopes considering the open problem raised in [M. Imran et al., families of plane graphs with constant metric dimension, Utilitas Math., in press] and finally Harary graphs H5,n by partially answering to an open problem proposed in Ⅱ. Javaid et al., Families of regular graphs with constant metric dimension, Utilitas Math., 2012, 88: 43-57]. We prove that these classes of regular graphs have constant metric dimension.
文摘We construct various cases for validity of the generalized second law(GSL)of thermodynamics by assuming the logarithmic correction to the horizon entropy of an evolving wormhole.It is shown that the GSL is always respected forα0≤0,whereas forα0>0 the GSL is respected only ifπr2A+/ℏ<α.