Fully relativistic, cosmological N-body simulations

In summary: No, I don't think that's necessary. It would just be a nice check to see if the effects are really there. :)In summary, non-linear effects may be relevant on cosmological scales, and fully relativistic simulations may be necessary to properly probe them.
  • #1
matt8282
5
0
Hi,

as you all know, current cosmological N-body simulations (like the Millenium run) are based on the Newtonian limit. Gravitational fields are supposed to be rather weak and therefore the force between dark matter particles reduces to Newtonian gravity. Other relativistic effects are neglected. The cosmological background expands independently of the non-linear processes inside the simulation box. In connection with backreaction studies it might be very useful to have fully-relativistic cosmological N-body simulations. I know that it is extremely difficult to simulate only two merging black holes with all relativistic effects so N-body codes might be completely out of reach. But still, I am interested in this topic. I am not aware of any work on this field.

Can anybody recommend me any article, paper, book or whatsoever? Any source of information is welcome.

Thank you very much in advance!

Best wishes,

Matt
 
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  • #2
What aspects do you think would require non-linear treatment on cosmological scales?
 
  • #3
Well, I don't really have a strong opinion on that. But there are claims that backreaction effects could mimic accelerated expansion (see Buchert, for instance) and standard N-body simulations suppress these effects by construction. So that's why I think it would be nice to check that in fully relativistic simulations (if possible..).

Again, any references concerning this are very welcome!
 
  • #4
The backreaction arguments, and associated large-scale inhomogenous concepts, have never been at all convincing to me---but I certainly don't understand them well enough to have a solid opinion. They are certainly not given much credence in the community.

In any case, these effects are only appreciable on scales comparable to the Hubble volume! Just about all long-duration cosmological structure formation simulations are entirely sub-Gpc scale... I just don't see any GR nonlinearities having any effect in that regime.
 
  • #5
Why fully relativistic? Surely you really don't need all that extra computation, and any kind simulation would be prohibitively expensive. The next step would presumably just be to include the lowest order corrections to Newtonian gravity, although I suspect these terms are neglected for a good reason ;)
 

FAQ: Fully relativistic, cosmological N-body simulations

1. What is a fully relativistic, cosmological N-body simulation?

A fully relativistic, cosmological N-body simulation is a computational model that simulates the behavior and interactions of a large number of particles (N) in a cosmological setting, taking into account the effects of both general relativity and cosmology. It aims to provide a more accurate and complete understanding of the evolution of structures in the universe.

2. How does a fully relativistic, cosmological N-body simulation work?

A fully relativistic, cosmological N-body simulation uses numerical methods to solve the equations of general relativity and cosmology, as well as Newton's laws of motion, to track the evolution of particles over time. The simulation also incorporates the effects of gravity, dark matter, and dark energy, which play significant roles in the large-scale structure of the universe.

3. What are the applications of fully relativistic, cosmological N-body simulations?

Fully relativistic, cosmological N-body simulations have a wide range of applications in astrophysics and cosmology. They can be used to study the formation and evolution of galaxies, clusters of galaxies, and large-scale structures in the universe. They can also help us understand the role of dark matter and dark energy in shaping the universe.

4. What are the challenges of conducting fully relativistic, cosmological N-body simulations?

Conducting fully relativistic, cosmological N-body simulations can be computationally expensive and require a significant amount of computing power. The simulation also needs to accurately model the complex interactions between particles, as well as the effects of general relativity and cosmology. Additionally, the initial conditions and parameters used in the simulation can greatly affect the results and must be carefully chosen.

5. How do fully relativistic, cosmological N-body simulations contribute to our understanding of the universe?

Fully relativistic, cosmological N-body simulations play a crucial role in advancing our understanding of the universe. They allow us to test different cosmological models and theories, and provide insights into the formation and evolution of structures in the universe. They also help us make predictions about the future of the universe and can guide future observational studies.

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