Questions tagged [de-sitter-spacetime]
149 questions
33
votes
2 answers
Why are anti-de Sitter spaces so interesting when we believe the universe is expansionary?
Perhaps this is a naive question, but in my recent (admittedly limited) readings about AdS spaces, I keep wondering why they seem to be such a hotbed for theoretical research (AdS/CFT correspondence, etc.). To my understanding, an AdS space has…
JotThisDown
- 1,474
15
votes
1 answer
Does de Sitter space admit an asymptotic S-matrix?
From the Penrose diagram of de Sitter space, we see it has a future and past conformal boundary, and they are both spacelike. So, does de Sitter space admit an asymptotic S-matrix? Sure, in the usual coordinates which only cover half of the full…
inflation
- 245
13
votes
4 answers
Can matter leave the cosmic horizon?
Cosmic horizon in the de Sitter space is a sphere, centered at the observer with finite radius where the red shift due to cosmic expansion becomes infinite.
Given that no information can be transmitted from behind the cosmic horizon, I wonder…
Anixx
- 11,524
13
votes
1 answer
Newton's law of gravitation in de Sitter space
Given two masses $M$ and $m$ (with $M\gg m$) in a de Sitter background with cosmological constant $\Lambda>0$ and positive spatial curvature ($k=+1$). What is the corresponding (semiclassical "Newtonian") gravitational force between $M$ and…
user56224
12
votes
2 answers
How is causal patch complementarity compatible with behavior during inflation?
Causal patch complementarity is the conjecture that in de Sitter space with a positive cosmological constant, the states within the causal patch are sufficient to fully describe the universe with the rest of the universe outside encoded within the…
10
votes
4 answers
de Sitter cosmological limit
It has been said that our universe is going to eventually become a de Sitter universe. Expansion will accelerate until their relative speed become higher than the speed of light.
So i want to understand what happens after this point: so from our…
lurscher
- 14,933
10
votes
1 answer
Black hole temperature in an asymptotically de Sitter spacetime
I am trying to calculate the Hawking temperature of a Schwarzschild black hole in a spacetime which is asymptotically dS. Ignoring the 2-sphere, the metric is given…
ScroogeMcDuck
- 1,262
9
votes
1 answer
Does the cosmological constant entail a mass for the graviton?
If I consider the Einstein equations into the form
$$
R_{\mu\nu}=\kappa \left(T_{\mu\nu}-\frac{1}{2}g_{\mu\nu}T\right)+\Lambda g_{\mu\nu}
$$
and then linearize them, we should get by moving to harmonic coordinates
$$
\Box g_{\mu\nu}=\Lambda…
Jon
- 4,184
9
votes
3 answers
If the expansion of the Universe accelerates, why its horizon does not shrink?
In de Sitter (expanding) universe to which our universe asymptotically approaches, the higher the rate of space expansion, the smaller the radius of the cosmic horizon. Why then our universe is thought of being accelerating expansion yet its radius…
Anixx
- 11,524
8
votes
2 answers
de Sitter Spacetime: Static patch vs Global coordinates
Two well-known coordinate charts on the dS spacetime are the global coordinates and the static patch coordinates. In the global coordinates, the D-dimensional dS metric takes the following form
$$ ds^2 = -dt_g^2 + l^2 \cosh^2(t_g/l)…
abhijit975
- 1,064
8
votes
1 answer
Does the background spacetime of a black hole affects its thermodynamic properties?
The question is this: will the thermodynamic properties of a black hole (Hawking radiation spectra and temperature, entropy, area, etc.) depend if the black hole sits in a DeSitter or an Anti-De-Sitter space-time?
Why and how?
lurscher
- 14,933
7
votes
2 answers
Is the de Sitter Universe static?
In the book Tolman R.C. Relativity, thermodynamics, and cosmology (3pr., Oxford, 1949) I read that the de Sitter Universe is static as well as the Einstein Universe.
But the de Sitter Universe is an expandable Universe.
I thought "static" meant…
Sergio
- 2,705
- 1
- 23
- 34
7
votes
0 answers
Resource Recommendation for black hole metrics in General Relativity
In classical textbooks for GR, Schwarzschild and Kerr spacetimes are adequately described. In which books or articles, it is mostly believed that Reissner–Nordstrom, Kerr–Newman, Schwarzschild–de Sitter, Kerr–de Sitter spacetimes are well described?
Constantin
- 658
7
votes
0 answers
A Universal Upper Limit on Mass Within a Radius $R$?
Since the universe has a positive cosmological constant, there is an upper limit on the mass of the black holes as evident from the so-called Schwarzschild-de Sitter metric:
$ds^2 = -f(r)dt^2 + \dfrac{1}{f(r)} dr^2 + r^2 d\Omega_2^2$
where, $f(r) =…
user87745
7
votes
1 answer
Why $C_{abcd}C^{abcd}$ in de Sitter–Schwarzschild metric doesn't depend on $\Lambda$
With the de Sitter–Schwarzschild metric:
$$ds^2=-\left(1-\frac{2M}{r}-\frac{\Lambda r^2}{3}\right)dt^2+\left(1-\frac{2M}{r}-\frac{\Lambda r^2}{3}\right)^{-1}dr^2+r^2d\theta+r^2\sin^2\theta d\phi$$
I can calculate the Riemann curvature tensor, Ricci…
346699
- 6,211