The universe content is considered as a non-perfect fluid with bulk viscosity and is described by a more general equation of state （endowed some deviation from the conventionally assumed cosmic perfect fluid model）....The universe content is considered as a non-perfect fluid with bulk viscosity and is described by a more general equation of state （endowed some deviation from the conventionally assumed cosmic perfect fluid model）. We assume the bulk viscosityis a linear combination of two terms： one is constant, and the other is proportional to the scalar expansion 0 = 3a/a. The equation of state is described as p = （γ - 1）p ＋ po, where po is a parameter. In this framework we demonstrate that this model can be used to explain the dark energy dominated universe, and different proper choices of the parameters may lead to three kinds of fates of the cosmological evolution： no future singularity, big rip, or Type-Ⅲ singularity as presented in IS. Nojiri, S.D. Odintsov, and S. Tsujikawa, Phys. Rev. D 71 （2005） 063004].展开更多
With entropic interpretation of gravity proposed by Verlinde, we obtain the Friedmann equation of the Friedmann Robertson-Walker universe for the deformed Hofava-Lifshitz gravity. It is shown that, when the parameter ...With entropic interpretation of gravity proposed by Verlinde, we obtain the Friedmann equation of the Friedmann Robertson-Walker universe for the deformed Hofava-Lifshitz gravity. It is shown that, when the parameter of Hofava-Lifshitz gravity ω →∞, the modified Friedmann equation will go back to the one in Einstein gravity. This results may imply that the entropic interpretation of gravity is effective for the deformed Hofava-Lifshitz gravity.展开更多
This article presents the hypothesis that the vacuum is endowed with a quantum structure;the vacuum particles would be Friedmann-Planck micro-universes. For this, the article introduces a quantization of a closed Frie...This article presents the hypothesis that the vacuum is endowed with a quantum structure;the vacuum particles would be Friedmann-Planck micro-universes. For this, the article introduces a quantization of a closed Friedmann universe, then a quantization of the photon spheres filling this universe. This approach gives a numerical value consistent with cosmological measurements for the current dark energy density of our Universe. Next, the article takes the content of a model published in Physics Essays in 2013 [<a href="#ref1" target="_blank">1</a>], assuming that elementary particles are Schwarzschild photon spheres;these could be derived from the Friedmann photon spheres composing the vacuum particles. It is further recalled that the model presents a unified structure of elementary particles and allows us to calculate the value of the elementary electric charge as well as the mass of the elementary particles.展开更多
Friedmann equation of cosmology is based on the field equations of general relativity. Its derivation is straight-forward once the Einstein’s field equations are given and the derivation is independent of quantum mec...Friedmann equation of cosmology is based on the field equations of general relativity. Its derivation is straight-forward once the Einstein’s field equations are given and the derivation is independent of quantum mechanics. In this paper, it is shown that the Friedmann equation pertinent to a homogeneous, isotropic and flat universe can also be obtained as a consequence of the energy balance in the expanding universe between the positive energy associated with vacuum and matter, and the negative gravitational energy. The results obtained here is a clear consequence of the fact that the surface area of the Hubble sphere is proportional to the total amount of information contained within it.展开更多
The first part of this article develops [1] a closed universe model deploying by identical multiplication a Friedmann-Planck micro-universe;thus this one constitutes the grains of the vacuum of this universe. The quan...The first part of this article develops [1] a closed universe model deploying by identical multiplication a Friedmann-Planck micro-universe;thus this one constitutes the grains of the vacuum of this universe. The quantum initial expansion of this is quadratic as a function of time. Using this model, calculating the density of matter at the present time gives a correct numerical result. The essential point is that during periods of expansion following the initial quadratic period, this model reveals a surprising phenomenon. The function expressing the radius curvature as a function of time depends on the individual mass of the heaviest elementary particles created at the end of the quadratic period. The model also leads to reflection on the dark matter. The second part imagines a new type of Big Rip based on the following hypothesis: when the acceleration of the Universe, caused by dark energy, reaches the value of Planck acceleration, destruction of the microscopic structure of the Universe occurs and is replaced by a macroscopic structure (photon spheres) identical to that of the initial Planck element. Thus a new Big Bang could begin on an immensely larger scale. This reasoning eventually leads to reflection on the origins of the Big Bang.展开更多
Assuming a flat universe expanding under a constant pressure and combining the first and the second Friedmann equations, a new equation, describing the evolution of the scale factor, is derived. The equation is a gene...Assuming a flat universe expanding under a constant pressure and combining the first and the second Friedmann equations, a new equation, describing the evolution of the scale factor, is derived. The equation is a general kinematic equation. It includes all the ingredients composing the universe. An exact closed form solution for this equation is presented. The solution shows remarkable agreement with available observational data for redshifts from a low of z = 0.0152 to as high as z = 8.68. As such, this solution provides an alternative way of describing the expansion of space without involving the controversial dark energy.展开更多
The quantum field theory on the universe model of closed Friedmann,i.e.the third quantization,is discussed in detail,and an abnormal distribution is given which is different from Hosoya’s result.
We propose a model for gravity based on the gravitational polarization of space. With this model, we can relate the density parameters within the Friedmann model, and show that dark matter is bound mass formed from ma...We propose a model for gravity based on the gravitational polarization of space. With this model, we can relate the density parameters within the Friedmann model, and show that dark matter is bound mass formed from massive dipoles set up within the vacuum surrounding ordinary matter. Aggregate matter induces a gravitational field within the surrounding space, which reinforces the original field. Dark energy, on the other hand, is the energy density associated with gravitational fields both for ordinary matter, and bound, or induced dipole matter. At high CBR temperatures, the cosmic susceptibility, induced by ordinary matter vanishes, as it is a smeared or average value for the cosmos as a whole. Even though gravitational dipoles do exist, no large-scale alignment or ordering is possible. Our model assumes that space, <i>i.e.</i>, the vacuum, is filled with a vast assembly (sea) of positive and negative mass particles having Planck mass, called planckions, which is based on extensive work by Winterberg. These original particles form a very stiff two-component superfluid, where positive and negative mass species neutralize one another already at the submicroscopic level, leading to zero net mass, zero net gravitational pressure, and zero net entropy, for the undisturbed medium. It is theorized that the gravitational dipoles form from such material positive and negative particles, and moreover, this causes an intrinsic polarization of the vacuum for the universe as a whole. We calculate that in the present epoch, the smeared or average susceptibility of the cosmos equals, <img src="Edit_77cbbf8c-0bcc-4957-92c7-34c999644348.png" width="15" height="20" alt="" />, and the overall resulting polarization equals, <img src="Edit_5fc44cb3-277a-4743-bfce-23e07f968d92.png" width="15" height="20" alt="" />=2.396kg/m<sup>2</sup>. Moreover, due to all the ordinary mass in the universe, made up of quarks and leptons, we calculate a net gravitational field having magnitude, <img src="Edit_c6fd9499-fe39-4d15-bc1c-0fdf1427dfd8.png" width="20" height="20" alt="" />=3.771E-10m/s<sup>2</sup>. This smeared or average value permeates all of space, and can be deduced by any observer, irrespective of location within the universe. This net gravitational field is forced upon us by Gauss’s law, and although technically a surface gravitational field, it is argued that this surface, smeared value holds point for point in the observable universe. A complete theory of gravitational polarization is presented. In contrast to electrostatics, gravistatics leads to anti-screening of the original source field, increasing the original value, <img src="Edit_a56ffe5e-10b9-4d3f-bf1e-bb52816fd07c.png" width="20" height="20" alt="" />, to, <img src="Edit_a6ac691a-342e-4ad4-9be0-808583f9f324.png" width="90" height="20" alt="" />, where <img src="Edit_69c6f874-5a3d-4d4a-84f7-819e06c09a83.png" width="20" height="20" alt="" style="white-space:normal;" /> is the induced or polarized field. In the present epoch, this leads to a bound mass, <img src="Edit_24ed50ca-84c2-4d3a-a018-957f7d0f964a.png" width="140" height="20" alt="" />, where <i>M<sub>F</sub></i> is the sum of all ordinary source matter in the universe, and <img src="Edit_5156dc24-3701-4491-9d10-58321e7d2d85.png" width="20" height="20" alt="" /> equals the relative permittivity. A new radius, and new mass, for the observable universe is dictated by the density parameters in Friedmann’s equation, and Gauss’s law. These lead to the very precise values, R<sub>0</sub>=3.217E27 meters, and, <i>M<sub>F</sub></i>=5.847E55kg, respectively, somewhat larger than current less accurate estimates.展开更多
This article gives a state-of-the-art description of the cosmological Lambda-CDM model and in addition, presents extensions of the model with new calculations of background and CMB functions. Chapters 1-4 describe the...This article gives a state-of-the-art description of the cosmological Lambda-CDM model and in addition, presents extensions of the model with new calculations of background and CMB functions. Chapters 1-4 describe the background part of the model, i.e. the evolution of scale factor and density according to the Friedmann equations, and its extension, which results in a correction of the Hubble parameter, in agreement with new measurements (Cepheids-SNIa and Red-Giants). Based on this improved background calculation presented in chapters 5-9 the perturbation part of the model, i.e. the evolution of perturbation and structure according to the perturbed Einstein equations and continuity-Euler equations, and the power spectrum of the cosmic microwave background (CMB) is calculated with a new own code.展开更多
基金The project partly supported by National Natural Science Foundation of China under Grant No. 10675062 and the Doctoral Foundation of China We thank Profs. I. Brevik, S.D. 0dintsov, and Lewis H. Ryder for lots of interesting discussions.
文摘The universe content is considered as a non-perfect fluid with bulk viscosity and is described by a more general equation of state （endowed some deviation from the conventionally assumed cosmic perfect fluid model）. We assume the bulk viscosityis a linear combination of two terms： one is constant, and the other is proportional to the scalar expansion 0 = 3a/a. The equation of state is described as p = （γ - 1）p ＋ po, where po is a parameter. In this framework we demonstrate that this model can be used to explain the dark energy dominated universe, and different proper choices of the parameters may lead to three kinds of fates of the cosmological evolution： no future singularity, big rip, or Type-Ⅲ singularity as presented in IS. Nojiri, S.D. Odintsov, and S. Tsujikawa, Phys. Rev. D 71 （2005） 063004].
基金Supported by the Program for New Century Excellent Talents in Universitythe National Natural Science Foundation of China under Grant No. 11075065+1 种基金the Fundamental Research Funds for the Central Universities under Grant Nos. lzujbky-2009-54, lzujbky-2009-163, and lzujbky-2009-122the Fundamental Research Fund for Physics and Mathematics of Lanzhou University under Grant No. LZULL200912
文摘With entropic interpretation of gravity proposed by Verlinde, we obtain the Friedmann equation of the Friedmann Robertson-Walker universe for the deformed Hofava-Lifshitz gravity. It is shown that, when the parameter of Hofava-Lifshitz gravity ω →∞, the modified Friedmann equation will go back to the one in Einstein gravity. This results may imply that the entropic interpretation of gravity is effective for the deformed Hofava-Lifshitz gravity.
文摘This article presents the hypothesis that the vacuum is endowed with a quantum structure;the vacuum particles would be Friedmann-Planck micro-universes. For this, the article introduces a quantization of a closed Friedmann universe, then a quantization of the photon spheres filling this universe. This approach gives a numerical value consistent with cosmological measurements for the current dark energy density of our Universe. Next, the article takes the content of a model published in Physics Essays in 2013 [<a href="#ref1" target="_blank">1</a>], assuming that elementary particles are Schwarzschild photon spheres;these could be derived from the Friedmann photon spheres composing the vacuum particles. It is further recalled that the model presents a unified structure of elementary particles and allows us to calculate the value of the elementary electric charge as well as the mass of the elementary particles.
文摘Friedmann equation of cosmology is based on the field equations of general relativity. Its derivation is straight-forward once the Einstein’s field equations are given and the derivation is independent of quantum mechanics. In this paper, it is shown that the Friedmann equation pertinent to a homogeneous, isotropic and flat universe can also be obtained as a consequence of the energy balance in the expanding universe between the positive energy associated with vacuum and matter, and the negative gravitational energy. The results obtained here is a clear consequence of the fact that the surface area of the Hubble sphere is proportional to the total amount of information contained within it.
文摘The first part of this article develops [1] a closed universe model deploying by identical multiplication a Friedmann-Planck micro-universe;thus this one constitutes the grains of the vacuum of this universe. The quantum initial expansion of this is quadratic as a function of time. Using this model, calculating the density of matter at the present time gives a correct numerical result. The essential point is that during periods of expansion following the initial quadratic period, this model reveals a surprising phenomenon. The function expressing the radius curvature as a function of time depends on the individual mass of the heaviest elementary particles created at the end of the quadratic period. The model also leads to reflection on the dark matter. The second part imagines a new type of Big Rip based on the following hypothesis: when the acceleration of the Universe, caused by dark energy, reaches the value of Planck acceleration, destruction of the microscopic structure of the Universe occurs and is replaced by a macroscopic structure (photon spheres) identical to that of the initial Planck element. Thus a new Big Bang could begin on an immensely larger scale. This reasoning eventually leads to reflection on the origins of the Big Bang.
文摘Assuming a flat universe expanding under a constant pressure and combining the first and the second Friedmann equations, a new equation, describing the evolution of the scale factor, is derived. The equation is a general kinematic equation. It includes all the ingredients composing the universe. An exact closed form solution for this equation is presented. The solution shows remarkable agreement with available observational data for redshifts from a low of z = 0.0152 to as high as z = 8.68. As such, this solution provides an alternative way of describing the expansion of space without involving the controversial dark energy.
基金the National Natural Science Foundation of China.
文摘The quantum field theory on the universe model of closed Friedmann,i.e.the third quantization,is discussed in detail,and an abnormal distribution is given which is different from Hosoya’s result.
文摘We propose a model for gravity based on the gravitational polarization of space. With this model, we can relate the density parameters within the Friedmann model, and show that dark matter is bound mass formed from massive dipoles set up within the vacuum surrounding ordinary matter. Aggregate matter induces a gravitational field within the surrounding space, which reinforces the original field. Dark energy, on the other hand, is the energy density associated with gravitational fields both for ordinary matter, and bound, or induced dipole matter. At high CBR temperatures, the cosmic susceptibility, induced by ordinary matter vanishes, as it is a smeared or average value for the cosmos as a whole. Even though gravitational dipoles do exist, no large-scale alignment or ordering is possible. Our model assumes that space, <i>i.e.</i>, the vacuum, is filled with a vast assembly (sea) of positive and negative mass particles having Planck mass, called planckions, which is based on extensive work by Winterberg. These original particles form a very stiff two-component superfluid, where positive and negative mass species neutralize one another already at the submicroscopic level, leading to zero net mass, zero net gravitational pressure, and zero net entropy, for the undisturbed medium. It is theorized that the gravitational dipoles form from such material positive and negative particles, and moreover, this causes an intrinsic polarization of the vacuum for the universe as a whole. We calculate that in the present epoch, the smeared or average susceptibility of the cosmos equals, <img src="Edit_77cbbf8c-0bcc-4957-92c7-34c999644348.png" width="15" height="20" alt="" />, and the overall resulting polarization equals, <img src="Edit_5fc44cb3-277a-4743-bfce-23e07f968d92.png" width="15" height="20" alt="" />=2.396kg/m<sup>2</sup>. Moreover, due to all the ordinary mass in the universe, made up of quarks and leptons, we calculate a net gravitational field having magnitude, <img src="Edit_c6fd9499-fe39-4d15-bc1c-0fdf1427dfd8.png" width="20" height="20" alt="" />=3.771E-10m/s<sup>2</sup>. This smeared or average value permeates all of space, and can be deduced by any observer, irrespective of location within the universe. This net gravitational field is forced upon us by Gauss’s law, and although technically a surface gravitational field, it is argued that this surface, smeared value holds point for point in the observable universe. A complete theory of gravitational polarization is presented. In contrast to electrostatics, gravistatics leads to anti-screening of the original source field, increasing the original value, <img src="Edit_a56ffe5e-10b9-4d3f-bf1e-bb52816fd07c.png" width="20" height="20" alt="" />, to, <img src="Edit_a6ac691a-342e-4ad4-9be0-808583f9f324.png" width="90" height="20" alt="" />, where <img src="Edit_69c6f874-5a3d-4d4a-84f7-819e06c09a83.png" width="20" height="20" alt="" style="white-space:normal;" /> is the induced or polarized field. In the present epoch, this leads to a bound mass, <img src="Edit_24ed50ca-84c2-4d3a-a018-957f7d0f964a.png" width="140" height="20" alt="" />, where <i>M<sub>F</sub></i> is the sum of all ordinary source matter in the universe, and <img src="Edit_5156dc24-3701-4491-9d10-58321e7d2d85.png" width="20" height="20" alt="" /> equals the relative permittivity. A new radius, and new mass, for the observable universe is dictated by the density parameters in Friedmann’s equation, and Gauss’s law. These lead to the very precise values, R<sub>0</sub>=3.217E27 meters, and, <i>M<sub>F</sub></i>=5.847E55kg, respectively, somewhat larger than current less accurate estimates.
文摘This article gives a state-of-the-art description of the cosmological Lambda-CDM model and in addition, presents extensions of the model with new calculations of background and CMB functions. Chapters 1-4 describe the background part of the model, i.e. the evolution of scale factor and density according to the Friedmann equations, and its extension, which results in a correction of the Hubble parameter, in agreement with new measurements (Cepheids-SNIa and Red-Giants). Based on this improved background calculation presented in chapters 5-9 the perturbation part of the model, i.e. the evolution of perturbation and structure according to the perturbed Einstein equations and continuity-Euler equations, and the power spectrum of the cosmic microwave background (CMB) is calculated with a new own code.
