Report: Brian Greene @ BYU

Brian Greene coming to BYU for the forum address was exciting for me in a few ways. First off Brian Greene came to BYU and secondly, I got to give the forum invocation and spend some extra time with Dr. Greene. It was a lot of fun to sit on the stand and feel 'all official' and then the fancy catered lunch afterwards was for 14 or so people in the Hinckley building. Anyway, I am sure that you're all not as interested in that stuff as I am, so I will move onto the meat of Dr. Greene's visit: string theory.

The address itself was very exciting; from Dr. Greene's initial wandering around the podium and his intensity to his great explanations of how the concepts of space and time have changed throughout the years. There were also two Q&A sessions: one right after the forum and then another for physics students later. I attended both and I will list, in bullet form, some points that he made.

• There is no stringy big bang model yet
• He does not 'believe in string theory' and will not until experimentally verified. It was nice to hear him say that
• Earth stays in orbit due warping in 'time.' I am not sure what he meant by that exactly
• Dark matter might be 'regular' matter hidden in extra dimensions
• Quantum foam is 'smoothed' out due to the minimum length scale introduced by strings. It does so because it prevents you from probing scales smaller than the string length. Also, this minimum length scale is what allows string theory to couple GR with quantum and it does not break Lorentz invariance
• As of now, there are no definite energies we need to probe at the LHC, but it could be soon when we get those numbers
• There are no practical application for string theory yet, but that's what they first thought when QM was first discovered
• String theory might come close to an eternal truth
• String theory unifies forces since all the force mediating particles come from the same strings
• Each of the 5 string theories is a different perturbative expansion

So that's a little of what Dr. Greene discussed. It really was a wonderful forum; he's a great speaker and is very enthusiastic about strings. You might be curious what he said when asked about rumors that string theorists are leaving string theory by the droves or what he thought about the last few books that claim string theory is wrong. He did address those issues and said that people are not abandoning string theory and that those books basically say the same that all string theorists say: that string theory has not yet been experimentally verified. Here is a link to the BYU NewsNet (not quite accurate) article reporting on the forum address.