In recent years string theory has been getting a lot of uninformed criticism about its supposed lack of progress towards the ultimate goal of a predictive theory that unifies the Standard Model and quantum gravity. Postings on this blog will be devoted to answering this criticism by highlighting and discussing recent string theory research, describing the progress that is being made.
The most dramatic advance in our understanding of fundamental physics coming out of string theory has been the realization that our universe is built on just one out of an exponentially large number of possible string theory metastable vacuum states. The theory of eternal inflation implies that we live in just one part of a multiverse containing regions with very different characteristics due to their very different vacuum states. This multiverse picture explains why string theorists have found it so difficult to make predictions, since the quantities involved are environmental rather than fixed by the fundamental string theory. This framework is described by Leonard Susskind as the “New Standard Model”, and as part of our discussion of progress in string theory, some postings will cover progress being made towards a predictive string theory-based multiverse framework.