Hi,

http://arxiv.org/abs/1211.0011

Newtonian N-body still valid approach to structure formation sims. even at large scales...

Note the acknowledgements section that suggests that the authors of this paper

discussed their results with the authors of the previous paper by Flender and Schwarz.

On Tuesday 10 of July 2012 12:45:52 Boud Roukema wrote:

> hi everyone

>

> http://arxiv.org/abs/1207.2035

> Newtonian versus relativistic cosmology

> Authors: Samuel F. Flender, Dominik J. Schwarz

>

> Abstract: We show how the relativistic matter and velocity power

> spectra behave in different gauges. We construct a new gauge where

> both spectra coincide with Newtonian theory on all

> scales. However, in this gauge there are geometric quantities

> present which do not exist in Newtonian theory, for example the

> local variation of the Hubble parameter. Comparing this quantity

> to second order Newtonian quantities, we find that Newtonian

> theory is wrong on scales larger than 10 Mpc. This undermines the

> reliability of Newtonian cosmological N-body simulations on these

> scales.

>

>

> What's surprising is that this is still only *perturbation* theory,

> it's not fully relativistic, if I understand the paper correctly.

> Fully relativistic calculations still remain to be done.

>

> pozdr

> boud

>

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--

================================================

Bartosz Lew

Nicolaus Copernicus University,

Torun Centre for Astronomy, Department of Radio-Astronomy

tel: +48 (56) 611 3042

email:blew@astro.uni.torun.pl, www: http://cosmos.astro.uni.torun.pl/~blew