[Cosmo-torun] cosmo workshop Fri 2 March @15.00 @KRA: Jan Ostrowski on Cactus: numerical relativity

[Boud Roukema]

hi cosmo-torun

   Cactus: numerical relativity
   cosmo workshop Fri 2 March @15.00 @KRA
   Jan Ostrowski


Jan is doing very interesting work in finding out how to do numerical
relativity. One way of saying it is the following:

"Normal" cosmological N-body simulations consist of *Newtonian*
gravity simulated on a highly simplified (perfectly homogeneous)
relativistic "background". In formal scientific language, this is
called a "heuristic" approach; in informal language, it's called "a
fudge" - it's a mathematical shortcut that seems like it should work
and lets us quickly compare some sort of "model" to observations
instead of waiting 50 years for the mathematics to be solved. In
principle, every scientist using the heuristic/fudge is aware of
this. Pure theory is very difficult to apply to the real world.

Relativistic cosmological simulations should be "directly"
relativistic, consistent with the Einstein equations, without using
the heuristic/fudge of adding "perturbations" that obey Newtonian
gravity to a relativistic "background". So these simulations can be called
"background-free".

How can we do background-free cosmology simulations?

Jan will present a discussion on this.

pozdr
boud