论文标题
宇宙常数在空间中多粒球的动力不稳定性
Dynamical instability of polytropic spheres in spacetimes with a cosmological constant
论文作者
论文摘要
相对论的多潮流球的动力不稳定性嵌入了具有排斥宇宙常数的时空中，在一般相对论的框架中研究了。我们应用了上一篇论文中使用的方法来研究以$λ= 0 $的捕获多变态球，即，临界点方法和Chandrasekhar开发的无限和绝热径向扰动方法。从数值上计算临界绝热索引，作为参数$σ= p _ {\ mathrm {c}}}/（ρ_{\ mathrm {c}} c^2）$的函数，对于宇宙学参数$λ$的几个值，给出了contrypoy $λ$的几个值。我们还通过使用两种方法来确定参数$σ_ {\ mathrm {cr}} $的临界值。我们发现，对于$σ_ {\ mathrm {cr}} $的值的参数$λ$的大值，由临界点方法计算出的差异与通过radial扰动方法获得的值不同。我们的结果通过两种应用方法给出，表明宇宙参数的巨大值$λ$对多流型配置的动态稳定性具有相关的影响。
The dynamical instability of relativistic polytropic spheres, embedded in a spacetime with a repulsive cosmological constant, is studied in the framework of general relativity. We apply the methods used in our preceding paper to study the trapping polytropic spheres with $Λ= 0$, namely, the critical point method and the infinitesimal and adiabatic radial perturbations method developed by Chandrasekhar. We compute numerically the critical adiabatic index, as a function of the parameter $σ= p_{\mathrm{c}}/(ρ_{\mathrm{c}} c^2)$, for several values of the cosmological parameter $λ$ giving the ratio of the vacuum energy density to the central energy density of the polytrope. We also determine the critical values for the parameter $σ_{\mathrm{cr}}$, for the onset of instability, by using both approaches. We found that for large values of the parameter $λ$, the differences between the values of $σ_{\mathrm{cr}}$ calculated by the critical point method differ from those obtained via the radial perturbations method. Our results, given by both applied methods, indicate that large values of the cosmological parameter $λ$ have relevant effects on the dynamical stability of the polytropic configurations.
