New inflationary universe

The new inflationary universe is a scenario in which the universe supercools by many orders of magnitude below the critical temperature of a phase transition predicted by grand unified theories, and in the process it expands exponentially by many orders of magnitude. The word new refers to a modification of the authors original proposal which was suggested independently by Linde and by Albrecht and Steinhardt. They suggested a new mechanism by which the phase transition could take place solving some crucial problems that were created by the authors original proposal. Unfortunately the new inflationary universe could not correctly account for the density fluctuations in the universe. The author views this not as a failure but as an encouraging near miss. Guth believes that the basic idea of inflation appears to be correct. It is a very simple and natural idea in the context of spontaneously broken gauge theories and it seems to solve some very fundamental cosmological problems. On the other hand the details are certainly not straight as the density fluctuations in the SU (5) new inflationary scenario turn out to be too large. The author believes that the cosmology is not working out right because the underlying particle physics is not correct in detail. 64 references, 1 figure