Holographic Chaplygin gas model
M R Setare
本文考虑了FRW宇宙中全息暗能量密度与Chaubergin气体能量密度的对应关系。在此基础上，我们重建了描述Chaobergin宇宙学的标量场的势场和动力学。
In this paper we consider a correspondence between the holographic dark energy density and Chaplygin gas energy density in FRW universe. Then we reconstruct the potential and the dynamics of the scalar field which describe the Chaplygin cosmology.
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Interacting holographic generalized Chaplygin gas model
本文考虑FRW宇宙中全息暗能量密度与相互作用广义Chaubergin气体能量密度之间的对应关系。在此基础上，我们重建了描述广义Chaobergin宇宙学的标量场的势。
Holographic Chaplygin DGP cosmologies
在本文中，我们提出了一个额外维度的启发模型，该模型是建立在DGP膜世界的情况下，然后我们把膜上的暗能量分量看作是一种Chaubergin气体。然后在DGP宇宙学的框架下考虑了Chaubergin气体的全息模型。我们表明，全息Chaubergin气体可以模仿一个幻影流体和跨越幻影划分DGP膜世界设置。
Modified Chaplygin Gas as Scalar Field and Holographic Dark Energy Model
分别研究了在平坦和非平坦FRW宇宙中，修正的Chaubergin气体（MCG）宇宙的场论和全息暗能量密度之间的对应关系.通过构造相应的势，我们给出了具有均匀最小耦合标量场的MCG的等价表示。得到了一个新的标量场势，它在物理上是真实的，对宇宙学模型的建立具有重要意义。此外，我们还提出了全息暗能量模型的MCG描述。通过重构非平坦宇宙中的势，确定了相应的全息暗能量场的动力学。本文还讨论了这种情况下全息暗能量在非平坦宇宙中的稳定性。
In this paper, we study the holographic dark energy density and interacting extended Chaplygin gas energy density in the Einstein gravity. We reconstruct the scalar field and the scalar potential describing the extended Chaplygin gas. In the special case, we obtain energy density and investigate some cosmological parameters. Assuming interaction between components we find energy density for some different parametrization of total EoS. We analyze tensor to scalar ratio and use recent observational data of BICEP2 to fix the model parameters.
Supersymmetric Chaplygin gas
使用卡鲁扎-克莱因框架，我们考虑一个相对论流体的投影产生的超对称非相对论Chaubergin气体介绍了伯格纳-Jackiw-Polychronakos和Hoppe。作为在扩展模型中产生的投影，得到了Chaubergin气体的守恒（超）电荷。
We establish a connection between the agegraphic models of dark energy and Chaplygin gas energy density in non-flat universe. We reconstruct the potential of the agegraphic scalar field as well as the dynamics of the scalar field according to the evolution of the agegraphic dark energy. We also extend our study to the interacting agegraphic generalized Chaplygin gas dark energy model.
I present a model in which dark energy interacts with matter. The former is represented by a variable equation of state. It is shown that the phantom crossing takes place at zero redshift, moreover, stable scaling solution of the Friedmann equations is obtained. I show that dark energy is most probably be either generalized phantom energy or the generalized Chaplygin gas.
Instability of holographic dark energy models
我们研究了全息暗能量、Chaubergin气体和常势快子模型之间的区别。为此目的，我们检查他们的平方声速的评估为零阶微扰理论，因此只依赖于时间。我们发现当选择未来事件视界作为红外截止点时，全息暗能量的速度平方总是负值，而Chaubergin气体和快子的速度平方是非负值.这意味着全息暗能量的完美流体是经典的不稳定。因此，Chaubergin气体和快子的全息解释是有问题的。
Chaplygin gas with field-dependent Poincare symmetry
在Duval的Kaluza-Klein框架下，利用普适的二次拉格朗日量，导出了Jackiw和Polychronakos提出的Chaubergin气体的相对论推广。我们的框架给出了依赖于场的庞加莱对称性的一个简化证明。我们的作用量与$d$ -膜的通常的南武-后藤作用量（世界体积）有关，就像弦理论中的波利亚科夫作用量和南武作用量一样。
Chaplygin electron gas model
本文提出了一种新的电磁质量模型，该模型考虑了Chaobergin气体状态方程.我们调查三个专业化，第一个特点是由一个消失的有效压力，第二个提供了一个恒定的有效密度和第三个是由一个恒定的有效压力。对于这些专业化的两个特殊情况下进行了讨论。此外，对于特化Ⅰ，我们发现了各向同性坐标以及Kretschmann标量，并为特化Ⅲ，情况II的两个特殊的情况进行了研究。
We investigate a model of interacting dark matter and dark energy given by a modified holographic Ricci cutoff in a spatially flat Friedmann-Robertson-Walker (FRW) space-time. We consider a nonlinear interaction consisting of a significant rational function of the total energy density and its first derivative homogeneous of degree one and show that the effective one-fluid obeys the equation of state of a relaxed Chaplygin gas. So that, the universe is dominated by pressureless dark matter at early times and undergoes an accelerated expansion in the far future driven by a strong negative pressu…
In the frame of the scalar field model with non minimal kinetic coupling to gravity, we study the cosmological solutions of the Chaplygin gas model of dark energy. By appropriately restricting the potential, we found the scalar field, the potential and coupling giving rise to the Chaplygin gas solution. Extensions to the generalized and modified Chaplygin gas have been made.
Remarks on the Generalized Chaplygin Gas
我们发展了广义Chaubergin气体（GCG）的作用量公式。导出了与物态方程一致的非相对论GCG作用量的最一般形式。我们还讨论了一个相对论制定GCG提供了详细的分析庞加莱代数。
The Chaplygin gas as a model for dark energy
本文综述了Chaobergin气体宇宙学模型的基本特征，并给出了Chaobergin气体状态方程在现代物理中出现的一些例子。讨论了Chaubergin气体在宇宙学中的一个可能的理论基础。讨论了它与标量场和快子宇宙学模型的关系。
In this paper, we consider a universe dominated by the extended Chaplygin gas which recently proposed as the last version of Chaplygin gas models. Here, we only consider the second order term which recovers quadratic barotropic fluid equation of state. The density perturbations analyzed in both relativistic and Newtonian regimes and show that the model is stable without any phase transition and critical point. We confirmed stability of the model using thermodynamics point of view.
Modified Chaplygin gas as an exotic fluid has been introduced in [34]. Essential features of the modified Chaplygin gas as a cosmological model are discussed. Observational constraints on the parameters of the model have been included. The relationship between the modified Chaplygin gas and a homogeneous minimally coupled scalar field are reevaluated by constructing its self-interacting potential. In addition, we study the role of the tachyonic field in the modified Chaplygin gas cosmological model and the mapping between scalar field and tachyonic field is also considered.
In this paper we consider the flat FRW cosmology with a scalar field coupled with the metric along with generalized Chaplygin gas and perfect fluid comprising the matter sector. We use the Schutz's formalism to deal with the generalized Chaplygin gas sector. The full theory is then quantized canonically using the Wheeler-DeWitt Hamiltonian formalism. We then solve the WD equation with appropriate boundary conditions. Then by defining a proper completeness relation for the self-adjointness of the WD equation we arrive at the wave packet for the universe. It is observed that the peak in the prob…
This manuscript investigate the dark energy Bianchi type-I cosmological models in presence of generalized Chaplygin gas, variable gravitational and cosmological constants. In this manuscript, exact solutions of Einstein field equations are obtained under the assumption of time periodic varying deceleration parameter. The physical and dynamical behaviors of the models have been discussed with the help of graphical representations. Also we have discussed the stability and physical acceptability of the obtained solutions
Transient acceleration from a hybrid Chaplygin gas
我们推广了Chaobergin气体模型的暗物质和暗能量统一促进Chaobergin气体参数A的潜在的额外标量与规范动能。混合模型允许加速哈勃膨胀是一个短暂的影响周围的红移为零。
Warm inflationary universe models in the context of generalized chaplygin gas, modified chaplygin gas, generalized cosmic chaplygin gas are being studied. The dissipative coefficient of the form $Γ\propto T$, weak and strong dissipative regimes are being considered. We use quartic potential $\frac{λ_{*}ϕ^{4}}{4}$, which is ruled out by current data in cold inflation but in our models it is analyzed that it is in agreement with the WMAP$9$ and latest Planck data. In these scenarios, the power spectrum, spectral index, and tensor to scalar ratio are being examined under the slow roll approximati…
In this paper, we considered an inflationary model that effectively behaves as a modified Chaplygin gas in the context of quintessence cosmology. We reconstructed the inflaton potential bottom-up and using the recent observational data we fixed the free parameters of the model. We showed that the modified Chaplygin gas inspired model is suitable for both the early and the late time acceleration but has shortcomings between the two periods.
In this paper, the model of interaction is studied between $f(T,\mathcal{T})$ gravity and modified Chaplygin gas in FRW-flat metric. We obtain the Friedmann equations in the framework of teleparallel gravity by vierbein field. We consider that Universe dominates by components of cold matter, dark energy and modified Chaplygin gas. In what follows we separately write the corresponding continuity equations for components of Universe. Also, dark energy EoS and effective EoS are obtained with respect to redshift, thereafter the corresponding cosmological parameters are plotted in terms of redshift…
We investigate the universe evolution from inflation to late-time acceleration in a unified way, using a two-component fluid constituted from extended Chaplygin gas alongside a phantom scalar field. We extract solutions for the various cosmological eras, focusing on the behavior of the scale factor, the various density parameters and the equation-of-state parameter. Furthermore, we extract and discuss bouncing solutions. Finally, we examine the perturbations of the model, ensuring about their stability and extracting the predictions for the tensor-to-scalar ratio.
Chaplygin gas dominated anisotropic brane world cosmological models
本文给出了以广义Chaubergin气体为物质源，Bianchi I型几何各向异性膜的广义Randall-Sundrum模型的引力场方程的精确解.广义的Chaobergin气体，它介于高密度相对论时代和非相对论物质阶段之间，是一种受欢迎的暗能量候选者。对于一个充满宇宙流体的Bianchi I型时空膜，当宇宙流体服从广义Chaubergin状态方程时，引力场方程的通解可以用一个精确的参数形式来表示，其中共动体积为参数.在压力等于能量密度的刚性宇宙流体的极限情况下，对于无压流体，场方程的解可以用精确的解析形式表示。还考虑了与Chaplygin流体相关的标量场的演化，并得到了相应的势。详细考虑了观测上重要的参数如剪切、各向异性和减速参数的行为。
In this paper, we investigate cosmological models of the extended Chaplygin gas in a universe governed by Horava-Lifshitz gravity. The equation of state for an extended Chaplygin gas is a $(n+2)$-variable equation determined by $A_{n}$, $α$, and $B$. In this work, we are interested to the case of second order $(n=2)$ equation of state which recovers quadratic barotropic equation of state. In that case there are four free parameters. We solve conservation equation approximately and obtain energy density in terms of scale factor with mentioned free parameters. Under some assumptions we relate fr…
Chaplygin-like gas and branes in black hole bulks
我们探讨了在黑洞块中定位膜的可能性。我们明确地研究了BHTZ和Schwarzschild-anti de Sitter（AdS）黑洞的情况。我们的结果是，在这些情况下，膜不能仅仅由膜张力支撑，必须在膜上引入其他形式的物质。我们发现类完美流体的解决方案，遵守特殊的状态方程。对于BHTZ体几何的情况下，状态方程采取的正是一个'' Chaubergin气体''的形式，这是相关的膜上下文。在Schwarzschild-AdS的情况下，我们找到了新的状态方程，当膜位于视界附近时，这些状态方程简化为Chaubergin形式。
We use the hybrid model of bulk viscosity and generalized chaplygin gas (GCG), named the viscous generalized chaplygin gas (VGCG) model, which is thought to be an alternate dark fluid of the universe. We explore the dynamics of the VGCG model in the framework of the non-metricity $f(Q)$ gravity using the functional form $f(Q)=βQ^n$, where $β$ and $n$ are arbitrary constants. For the purpose of constraining model parameters, we use recent observational datasets such as Observational Hubble data, Baryon Acoustic Oscillations, and Type $Ia$ supernovae data. According to our study, the evolution o…
Chaplygin gas with non-adiabatic pressure perturbations
如果允许参数$A$的空间变化，则由状态方程$p = -A/ρ$表征的Chaubergin气体中的扰动可以获得非绝热贡献。这一功能被证明是相关的一个特定的内部结构的Chaubergin气体。我们研究了这种类型的扰动如何改变绝热声速和影响引力势的时间依赖性，从而引起积分萨克斯-沃尔夫效应的各向异性谱的宇宙微波背景。
The Modified Chaplygin Gas (MCG) model belongs to the class of a unified models of dark energy (DE) and dark matter (DM). It is characterized by an equation of state (EoS) $p_c = Bρ- A/ρ^α$, where the case $B=0$ corresponds to the Generalized Chaplygin Gas (GCG) model. Using a perturbative analysis and power spectrum observational data we show that the MCG model is not a sucessful candidate for the cosmic medium unless $B=0$. In this case, it reduces to the usual GCG model.
In this paper, we propose extended Chaplygin gas equation of state for which it recovers barotropic fluid with quadratic equation of state. We use numerical method to investigate the behavior of some cosmological parameters such as scale factor, Hubble expansion parameter, energy density and deceleration parameter. We also discuss about the resulting effective equation of state parameter. Using density perturbations we investigate the stability of the theory.
Interacting Chaplygin gas
研究了一类相互作用的Chaubergin气体模型，其中Chaubergin气体扮演着暗能量的角色，与冷的暗物质粒子相互作用.我们发现，在宇宙演化到稳态阶段的后期，存在一个稳定的标度解。此外，Chaubergin气体的有效状态方程可以跨越所谓的幻影鸿沟$w=-1$。上述结果是从连续性方程导出的，这意味着它们独立于任何引力理论。假设标准广义相对论和空间平坦的FRW度规，我们还发现减速参数与当前的观测结果是一致的。
Newtonian Approach to the Matter Power Spectrum of the Generalized Chaplygin Gas
我们将宇宙介质建模为广义Chaubergin气体和无压物质组分的混合物。在一个新牛顿的方法，我们计算的物质功率谱。的2dFGRS数据被用来区分统一的模型的黑暗部门和不同的模型，其中有单独的暗物质，除了占广义Chaubergin气体。如果不考虑相应的密度参数，我们发现统一模型是非常不利的。另一方面，使用统一的模型先验，观测数据也得到了很好的描述，特别是对于小的和大的值的广义Chaubergin气体参数$α$。
The role of the interaction in reaching and crossing the phantom divide line in the Chaplygin gas model is discussed. We obtain some necessary properties of the interaction that allow the model to arrive at or cross the phantom divide line. We show that these properties put some conditions on the ratio of dark matter to dark energy density in the present epoch.
Gauge-invariant analysis of perturbations in Chaplygin gas unified models of dark matter and dark energy
我们利用规范不变的形式主义来分析两个宇宙学模型的微扰行为的基础上广义Chaubergin气体描述暗物质和暗能量在目前的宇宙。在第一个模型中，我们只考虑广义Chaobergin气体，而在第二个模型中，我们加入了重子分量，并将我们的分析扩展到参数范围$α> 1$中，在这个参数范围中，广义Chaobergin气体的声速可以大于光速。在第一个模型中，我们发现，物质的功率谱与观测到的一致，只有$α< 10^{-5}$，这使得广义Chaubergin气体实际上是无法区分的$Λ$ CDM。在第二个模型中，我们研究了重子分量不均匀性的演化。对于几乎所有的$α$值，理论功率谱都与观测功率谱吻合得很好。然而，不均匀性的增长似乎特别有利于足够小的$α$值或$α\gtrsim 3$。因此，当广义Chaubergin气体的声速是超光速时，它作为宇宙学模型的可行性似乎更强。我们表明，在这种情况下，广义Chaubergin气体状态方程可以改变在一个不可观测的区域，以这样一种方式，其等效的$k$本质微观模型没有问题的因果关系。
Viscous dissipative Chaplygin gas dominated homogenous and isotropic cosmological models
广义的Chaobergin气体，它介于高密度相对论时代和非相对论物质阶段之间，是一种受欢迎的暗能量候选者。我们考虑一个推广的Chaubergin气体模型，通过假设存在一个散装粘性型耗散项的气体的有效热力学压力。耗散效应用截断的Israel-Stewart模型来描述，体粘滞系数和弛豫时间仅为能量密度的函数。在平坦均匀各向同性的Friedmann-Robertson-Walker几何中，详细研究了体粘滞Chaubergin气体支配宇宙的宇宙动力学.对于不同的模型参数值，我们考虑宇宙学参数（标度因子，能量密度，哈勃函数，减速参数和光度距离，分别）的演变，通过使用解析和数值方法。在大的时间限制的模型描述了一个加速的宇宙，与有效的负压力引起的Chaubergin气体和体粘滞压力驱动的加速。我们的模型的光度距离的理论预测的Ia型超新星的观测进行了比较。该模型与最近的超新星数据吻合得很好。从拟合，我们确定的状态方程的Chaubergin气体，和表征体积粘度的参数。同时考虑了粘性Chaubergin流体的标量场的演化，得到了相应的势。因此，粘性Chaubergin气体模型提供了一个有效的动力学可能性，以取代宇宙学常数，并解释最近的宇宙加速。
We consider a Chaplygin gas model with an exponential potential in framework of braneworld inflation. We apply the slow-roll approximation in the high-energy limit to derive various inflationary spectrum perturbation parameters. We show that the inflation observables depend only on the e-folding number N and the final value of the slow-roll parameter e(end). Whereas for small running of the scalar spectral index dns/dlnk, the inflation observables are in good agreement with recent WMAP7 data.
Chaplygin Gas Cosmology - Unification of Dark Matter and Dark Energy
由于绝热声速对结构形成的抑制，基于查伯金气体统一暗物质和暗能量的模型失败了。包括弦论的影响，特别是在卡尔布-雷蒙场，我们展示了如何非绝热扰动允许一个成功的结构形成。
Matter Power Spectrum for the Generalized Chaplygin Gas Model: The Newtonian Approach
我们将宇宙介质建模为广义Chaubergin气体和无压物质组分的混合物。在一个新牛顿的方法（其中，不同于标准的牛顿宇宙学，压力进入均匀和各向同性的背景动力学），我们计算的物质功率谱。2dFGRS的数据被用来区分统一模型的暗扇区（一个纯粹的重子物质的组成部分，约占总能量的5%和约95%的广义Chaubergin气体）和不同的模型，其中有单独的暗物质，除了由广义Chaubergin气体占。如果不考虑相应的密度参数，我们发现统一模型是非常不利的。另一方面，使用统一的模型先验，观测数据也得到了很好的描述，特别是对于小的和大的值的广义Chaubergin气体参数$α$。后者的结果是在最近的协议，更定性，但完全相对论，在Gorini等人的微扰分析。
We have considered flat Friedmann-Robertson-Walker (FRW) model of the universe and reviewed the modified Chaplygin gas as the fluid source. Associated with the scalar field model, we have determined the Hubble parameter as a generating function in terms of the scalar field. Instead of hyperbolic function, we have taken Jacobi elliptic function and Abel function in the generating function and obtained modified Chaplygin-Jacobi gas (MCJG) and modified Chaplygin-Abel gas (MCAG) equation of states, respectively. Next, we have assumed that the universe filled in dark matter, radiation, and dark ene…
The class of Chaplygin gas models regarded as a candidate of dark energy can be realized by a scalar field, which could drive the variation of the fine structure constant $α$ during the cosmic time. This phenomenon has been observed for almost ten years ago from the quasar absorption spectra and attracted many attentions. In this paper, we reconstruct the class of Chaplygin gas models to a kind of scalar fields and confront the resulting $Δα/α$ with the observational constraints. We found that if the present observational value of the equation of state of the dark energy was not exactly equal …
In this paper, we investigate the viscous modified Chaplygin gas cosmological model. Solutions for different values of the viscosity parameter are obtained using both analytical and numerical methods. We have calculated the deceleration and defined {\em newly} statefinder $\{r, s \}$ pair in D dimensions. It is shown that when $D=4$, the usual statefinder parameters are recovered. Furthermore, we apply the statefinder diagnostic to the MCG model with and without viscosity in $D$ dimensions and explore these parameters graphically.
Tsallis holographic dark energy with power law ansatz approach
本文研究了Tsallis holographic dark energy模型，通过幂律假设方法探讨了粘性、非粘性及Chaplygin气体三种宇宙学场景，分析了模型的稳定性及 phantom divide 交叉特性。
The generalized Chaplygin gas (GCG) model is the prototype of a unified model of dark energy (DE) and dark matter (DM). It is characterized by equation-of-state (EoS) parameters $A$ and $α$. We use a statistical analysis of the 2dFGRS data to constrain these parameters. In particular, we find that very small (close to zero) and very large values ($α\gg 1$) of the equation-of-state parameter $α$ are preferred. To test the validity of this type of unification of the dark sector we admit the existence of a separate DM component in addition to the Chaplygin gas and calculate the probability distri…
In this paper, we investigate cosmological consequences of a scenario for recently reported accelerated expansion of the Universe, in which the generalized Chaplygin gas (GCG) along with the baryonic matter are responsible for this observed phenomenon. In the present model, we employ an isotropic and homogeneous FLRW space time in the framework of $f(R,T)$ theory of gravity. In $f(R,T)$ gravity, the conservation of energy-momentum tensor (EMT) leads to a constraint equation which enforces us to use some specific forms of type $f(R,T)=g(R)+h(T)$. In this work we choose $g(R)=R$. We consider thr…
Generalizing the generalized Chaplygin gas
广义Chaobergin气体的特征在于状态方程p = - A/rho^alpha，其中alpha > -1和w >-1。我们将此模型推广到允许alpha < -1或w <-1的情况。这种推广导致了广义Chaubergin气体的三个新版本：早期模型，其中在早期w << -1，在晚期渐近接近w = -1;晚期模型，其中在早期w \approx -1，在晚期w -> - \infty;以及瞬态模型，其中在早期w \approx -1，在晚期w -> 0。我们认为这三种情况下的暗能量模型单独和检查约束Ia型超新星和从地平线下的密度扰动的增长。瞬态Chaobergin气体模型提供了一种可能的机制，允许当前加速的宇宙没有未来视界，而一些早期的幻影模型产生w < -1，没有过去或未来的奇点。
In the simplest scenario for inflation, i. e. in the single-field inflation, it is presented an inflaton field with properties equivalent to a generalized Chaplygin gas. Their study is performed using the Hamilton-Jacobi approach to cosmology. The main results are contrasted with the measurements recently released by the Planck data, combined with the WMAP large-angle polarization. If the measurements released by Planck for the scalar spectral index together with its running are taken into account it is found a value for the $α$-parameter associated to the generalized Chaplygin gas given by $α…
In this paper, we study the Chaplygin gas Hořava-Lifshitz quantum cosmology. Using Schutz formalism and Arnowitt-Deser-Misner decomposition, we obtain the corresponding Schrödinger-Wheeler-DeWitt equation. We obtain exact classical and quantum mechanical solutions and construct wave packets to study the time evolution of the expectation value of the scale factor for two cases. We show that unlike classical solutions and upon choosing appropriate initial conditions, the expectation value of the scale factor never tends to the singular point which exhibits the singularity-free behavior of the so…
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