与 Christof Schmidhuber
有关膜宇宙论的通信
(信件片段)
|
Date: Sat, 4 Oct 2003 23:45:37 -0400 (EDT) Dear Dr. Schmidhuber, ... ... Recently, I noticed your theory on Micrometer Gravitinos and the Cosmological Constant. I'm very impressed by your idea, and have written an article to introduce the cosmological constant problem and especially your theory to the theorists in China (I'm from China). As I'm thinking about your theory, however, there is one question I'm still wondering. According to your theory (and many other brane cosmological models), the standard model fields on the brane only contribute to the curvature transverse to the brane. The question I have is how can this concept be made compatible with the senario of inflation in which the cosmological constant generated by standard model fields does (and seems must) contribute to the curvature of the 4-D spacetime? I will be very glad to hear your opinion on this problem. Thank you very much for your time and sorry for the disturbance.
Sincerely Yours,
Date: Tue, 4 Nov 2003 21:04:40 +0100 (CET) Dear Changhai, Thank you for your mail, it is nice to see that you are also intrigued by the fact that the brane world scenario seems to have the potential of having a cosmological constant that has just the right order of magnitude. Your question about the cosmological constant during inflation is a good one, though, and I am afraid I do not have a simple answer. I have mostly thought about the static scenario, where the vacuum energy is approximately constant on the brane. During the phase transition in which the Higgs rolled down its potential and created a cosmological constant, this was certainly not the case; it is unlikely that this transition happened everywhere at once. So I can well imagine that this leaves enough room for an expanding brane-universe, but I have not really studied it. I believe it is an interesting problem, though.
With Best Regards, |