1
$\begingroup$

I wonder why can SUGRA actions be used in string cosmology, since in some cases they are used to model big bang scenarios (for example the pre big bang scenario in chapter 4 of Gasperini's "Elements of string cosmology"). Shouldn't the energy scale be so high that actual superstring theory needs to be used, instead of its low energy description?

$\endgroup$
1
$\begingroup$

If the energy scale is much less than the string energy scale, which is supposedly around the Planck mass, then SUGRA is a good approximation.

For instance inflationary energy scale (by which I mean mass of an inflaton) is around $M_I\sim 10^{14}$ GeV, give or take depending on the model. Clearly $M_I\ll M_P$.

Unfortunately I don't have that book, so cannot comment on that model you mention.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.