# Questions tagged [de-sitter-spacetime]

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### De Sitter horizon area increase

Black holes increase area when any object falls past the horizon. Note: We define "when" as when the hair from the object falling in becomes undetectable for distant observers. It would also ...
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### Is there a smooth, spherically symmetric, static, asymptotically de Sitter spacetime of constant scalar curvature?

...other than de Sitter space itself? Two clarifications: I am not talking about solutions of Einstein's equations, just spacetimes. So, general Lorentzian manifolds. I am not counting, for example,...
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### Construction of Carter-Penrose diagram for DeSitter spacetime

The DeSitter spacetime line element in global coordinates is given by $$ds^2 = -dt^2 + \frac{1}{H^2}\cosh^2(Ht)\left(d\chi^2 + \sin^2(\chi)(d\theta^2 + \sin^2(\theta)d\phi^2 \right).$$ The ranges of ...
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### Bose-Einstein statistics in de Sitter spacetime

The metric in de Sitter spacetime with $(+,-,-,-)$ as metric signature is, in cartesian coordinates: \begin{equation} ds^2=dt^2-a^2(t)(dx^2+dy^2+dz^2). \end{equation} Where $a(t)=e^{Ht}$. How do I ...
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### Question regarding different mode functions in FRW spacetime

I am currently reading Mukhanov's and Winitzki's book with title: "Introduction to Quantum Fields and Classical Backgrounds". At chapter 6, they argue that in a FRW (Freedman - Robertson - ...
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### What happens to the information content of the universe in the deSitter phase?

What happens to the information content of the universe when the accelerated expansion enters the empty deSitter phase in the distant future?
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### Interpretation of horizon in de Sitter

Given the de Sitter metric for spacetime $$ds^2 = \left( 1 - \frac{\Lambda}{3}r^2\right) dt^2 - \frac{1}{\left( 1 - \frac{\Lambda}{3}r^2 \right)}dr^2 - r^2d\Omega^2$$ we understand this is a solution ...
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### de-Sitter space as near-horizon limit of Black Holes

We know that we can obtain $AdS_{2}$ x $S_{2}$ spacetime as the near-horizon geometry of an extremal/ near extremal RN (or Kerr) Black Hole in asymptotically flat spacetime. It is also known that we ...
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### Is de Sitter space homogeneous?

Since Minkowski and anti de Sitter are homogeneous Lorentzian manifolds, it is natural to ask if de Sitter is too, but nobody ever discusses this. In Riemannian geometry a globally symmetric complete ...
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### Jacobi Identity in de Sitter Superalgebra

In the book "Supergravity" (by D. Freedman and A. Van Proeyen) they talk about why $\mathcal{N}=1$ de-sitter superalgebra is impossible to construct (Section 12.6.1). Basically de-Sitter algebra is a ...
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### Maximally symmetric spaces

In GR, what is the most precise definition of a maximally symmetric spacetime? Also, we study about the temporal boundary of dS space, and a spatial boundary of AdS space, but aren't these spaces ...
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### De sitter spacetime and co-ordinates

I was recently looking at de - Sitter spacetime and I relaized that there are many different parameterizations possible, each of which has it's own advantages. Can someone help me out and list the ...
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### Can String Theory really fail to contain a de Sitter vacua?

I was reading a post earlier from Peter Woit's Not Even Wrong blog and came across the following reference to the paper "What if string theory has no de Sitter vacua?" by Ulf H. Danielsson, Thomas Van ...