In order to understand how locally static configurations around gravitationally bound bodies can be embedded in an expanding universe, we investigate the solutions of general relativity describing a space-time whose spatial sections have the topology of a 3-sphere with two identical masses at the poles. We show that Israel junction conditions imply that two spherically symmetric static regions around the masses cannot be glued together. If one is interested in an exterior solution, this prevents the geometry around the masses to be of the Schwarzschild type and leads to the introduction of a cosmological constant. The study of the extension of the Kottler space-time shows that there exists a non-static solution consisting of two static regions surrounding the masses that match a Kantowski-Sachs expanding region on the cosmological horizon. The comparison with a Swiss-Cheese construction is also discussed.
The complete relativistic kinetic model of violation of symmetry in isotopic expanding plasma and production of baryons in hot Universe. I. Exact model
The effect of an expanding universe on massive objects
我们提出了一些天体物理学的后果的度量的质点在膨胀的宇宙在Nandra，Lasenby和霍布森，和相关的不变表达式的力保持测试粒子在相对于中心质量静止。我们专注于膨胀的宇宙对星系和星系团规模的大质量物体的影响。使用牛顿和广义相对论的方法，我们确定了两个重要的时间依赖性的物理半径为这样的对象时，宇宙膨胀加速。第一半径$r_F$是测试粒子上的总径向力为零的半径，其也是围绕中心质量$m$的最大可能圆形轨道的半径，并且在该半径处气体压力及其梯度为零。第二个半径$r_S$，即\approx r_F/1.6 $, is that of the largest possible stable circular orbit, which we interpret as the theoretical maximum size for an object of mass $ m $. In contrast, for a decelerating cosmological expansion, no such finite radii exist. Assuming a cosmological expansion consistent with a $ Λ$CDM协调模型，在目前的时间里，我们发现这些半径对星系和星系团的典型尺寸都有明显的限制。对于星系，我们还发现，这些半径同意密切与零附近的星系，P…
We examine a quantised massive scalar field in $(1+1)$-dimensional spatially compact cosmological spacetimes in which the early time and late time expansion laws provide distinguished definitions of Fock "in" and "out" vacua, with the possible exception of the spatially constant sector, which may become effectively massless at early or late times. We show, generalising the work of Ford and Pathinayake, that when such a massive zero mode occurs, the freedom in the respective "in" and "out" states is a family with two real parameters. As an application, we consider massive untwisted and twisted …
The Lorentzian type IIB matrix model is a promising candidate for a non-perturbative formulation of superstring theory. However, it was found recently that a Euclidean space-time appears in the conventional large-$N$ limit. In this work, we add a Lorentz invariant mass term to the original model and consider a limit, in which the coefficient of the mass term vanishes at large $N$. By performing complex Langevin simulations to overcome the sign problem, we observe the emergence of expanding space-time with the Lorentzian signature.
Future stability of expanding spatially homogeneous FLRW solutions of the spherically symmetric Einstein--massless Vlasov system with spatial topology $\mathbb{R}^3$
We study the black-box parameter estimation of expanding parameters and the dynamics of Gaussian interferometric power for the de Sitter space. We find that the state between separated open charts can be employed as probe state for the black-box quantum metrology. This is nontrivial because the open charts are causally disconnected and classical information can not be exchanged between them according to the general relativity. It is shown that the mass of the scalar field remarkably affects the accuracy of the black-box parameter estimation in the de Sitter space, which is quite different from…
