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arXiv 1306.0917astro-ph.CO
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非绝热Chaobergin气体

Non-adiabatic Chaplygin gas

H. A. Borges, S. Carneiro, J. C. Fabris, W. Zimdahl

摘要:

状态方程为p = -A/ρ^α的广义Chaobergin气体分裂为状态方程为p_Λ = - ρ_Λ的无压物质和暗能量组分的相互作用混合物,这意味着存在非绝热压力扰动。我们证明了介质的有效(非绝热)声速cs的平方正比于暗能量扰动与暗物质扰动的比值。因为,正如在α= -1/2的特殊情况下明确证明的那样,与暗物质在与结构形成相关的尺度上的扰动相比,暗能量扰动可以忽略不计,我们发现|c_s^2| << 1.因此,没有振荡或不稳定性,困扰以前的绝热Chaubergin气体模型。

英文摘要:

The split of a generalised Chaplygin gas with an equation of state p = -A/ρ^α into an interacting mixture of pressureless matter and a dark-energy component with equation of state p_Λ = - ρ_Λ implies the existence of non-adiabatic pressure perturbations. We demonstrate that the square of the effective (non-adiabatic) sound speed c_s of the medium is proportional to the ratio of the perturbations of the dark energy to those of the dark matter. Since, as demonstrated explicitly for the particular case α= -1/2, dark-energy perturbations are negligible compared with dark-matter perturbations on scales that are relevant for structure formation, we find |c_s^2| << 1. Consequently, there are no oscillations or instabilities which have plagued previous adiabatic Chaplygin-gas models.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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