I still haven’t figured out yet what the arXiv’s trackback policy is, since trackbacks to my blog entries sometimes appear there, sometimes not. One example in the “not” category is my recent posting about the Kumar-Taylor paper on “String Universality”, which now has trackbacks to postings by Jacques Distler (recently seen here) and Dmitry Podolsky. The ways of the arXiv remain mysterious, but I can’t help recalling that my original problems with them seemed to have to do with powerful people who did not like having their multiverse pseudo-science disrespected. Even without the trackback, I’m wondering if the authors of the paper somehow heard about my comments and felt they needed to be addressed, since a new version of the paper has just appeared.
The most extensive changes are to the section on “predictivity” discussed in my posting. Here’s some of the added text:
It may be that string universality holds for four-dimensional theories with supersymmetry, but that supersymmetry breaking mechanisms lead to a constrained subset of non-supersymmetric low-energy theories in 4D.
It is possible that the dynamics of string cosmology may define a natural measure on the space of string solutions, which would favor some solutions over others. Currently, however, we lack a mathematically complete or background-independent formulation of string theory. It is likely that significant progress in this direction will be needed to understand the cosmological measure on the string landscape. In this brief discussion, we describe the situation for predictivity in the absence of such a breakthrough.
Some other changes:
This may seem like a very awkward situation for string theory.
has been replaced by
If we were living in six dimensions, then this would seem like a very awkward situation for string theory.
and the assurance that string theory would explain anything seen at the LHC has been toned down a bit, with
any new and unexpected phenomena found in experiments at higher energies should be realizable in the string theory context
any new and unexpected phenomena found in experiments at higher energies may be realizable in the string theory context