A Graceful exit of a cosmological inflation model

[Alpha2021]

How to determine whether a cosmological inflation model (say single-field slow-roll inflation) gracefully exit or not? Is it like showing that inflation is ending at some value of inflaton?

 

[Will Learn]

Hi.
You're not getting a lot of responses, so I hope this will be of some help.

Have you got access to a library? My main source of information is "The History of the Universe", David H Lyth, publisher: Springer, 2016

It's a short book which (in my opinion) is suitable for post-graduates in a rush. It describes all the required effects of inflation on pages 71~73. However, it's in the Appendix on page 102 where some criteria for the end of inflation are established. So the whole lot is no more than 4 or 5 pages of A5 size... or 10 minutes reading (and in my case, twice as long figuring out what was going on with your own pencil and paper).

I could repeat what is said there but I can't do it any better than the original text. I read it at speed and wasn't really concerned about this aspect anyway.

Assuming I understood the text, Lyth presents criteria on V'' that mark the end of inflation.

Best Wishes.

LATE EDITING: According to the info on the back of the book, the book is appropriate for the general public EXCEPT the appendix (the thing is without the appendix you've got nothing much except some nice words anyway).

 

[Alpha2021]

Hi.
You're not getting a lot of responses, so I hope this will be of some help.

Have you got access to a library? My main source of information is "The History of the Universe", David H Lyth, publisher: Springer, 2016

It's a short book which (in my opinion) is suitable for post-graduates in a rush. It describes all the required effects of inflation on pages 71~73. However, it's in the Appendix on page 102 where some criteria for the end of inflation are established. So the whole lot is no more than 4 or 5 pages of A5 size... or 10 minutes reading (and in my case, twice as long figuring out what was going on with your own pencil and paper).

I could repeat what is said there but I can't do it any better than the original text. I read it at speed and wasn't really concerned about this aspect anyway.

Assuming I understood the text, Lyth presents criteria on V'' that mark the end of inflation.

Best Wishes.

LATE EDITING: According to the info on the back of the book, the book is appropriate for the general public EXCEPT the appendix (the thing is without the appendix you've got nothing much except some nice words anyway).

Thanks a lot for this kind reply.

The pages numbers saved my time to find the chapter. (sorry for the late reply.
Are you saying that violation of conditions ε, η≈1 can be called a graceful exit of inflation (slow roll)? Is it sufficient?

 

[Will Learn]

Hi again.

I don't consider myself an expert on Inflation. My advice is limited. I also don't check the forum often, so don't wait for me to reply. It could be weeks.

Is it sufficient?

I've spent a bit more time and read the pages in the book again. Actually, there is a risk that the conditions described in the appendix are just necessary conditions. Lyth does seem to refer to the entire proposed shape of the inflaton potential (fig 14.1 in the book) as being required to guarantee an exit from inflation.

Your original post seemed to ask for criteria to determine if inflation has ended and/or if (the usual model of) the inflaton field provides a graceful exit from inflation. Lyth's book describes this. So I hope that wasn't a waste of your time.

Your second post suggests that you might be trying to develop a whole new shape for the inflaton potential and wanted some sufficient conditions to check this will give you a graceful exit from inflation. That's quite different thing and I don't think Lyth's book will help much with that, sorry.

Best Wishes.