Above is an interactive timeline detailing key events in the development of string theory. Click on the name of each event for a more detailed description. In these descriptions you will find links to key terms and major actors at their first appearance.
Above is a graph of the number of string theory papers published per year from 1973 onward, as catalogued by the ISI Web of Science. As you can see, from 1973 to 1985 the output of string theory papers was very low. A jump in paper output after 1985 can be easily observed, corresponding to the first superstring revolution mentioned above. After 1990, the number of papers published per year greatly increases again. From the timeline, we see that this can be attributed to growing interest in dualities between different string theories. From 1994 to 1999, paper output increases steadily each year, corresponding with the events of the second superstring revolution. A distinct jump can be seen between 1997 and 1998, due to the discovery of the AdS/CFT correspondence and the wave of new research it sparked. Afterwards, string theory paper output levels off, with a small increase in 2007 and 2008 which cannot be explained by any one key research development.
To add a geographical dimension to the graph of paper output above, here we have included a breakdown of the percentage of string theory papers published in various countries each year from 1983 onward (as is evident from the preceding graph, geographical data from 1973 to 1982 would not be extremely meaningful due to the small number of string theory papers published during those years). Tracking the proportion of papers coming from the United States, we see that they played a crucial role in early developments during the first superstring revolution, and then tapered off to a 25% contribution per year in recent time as more countries entered the field. Also of interest is the contribution of Switzerland. We see from the graph that in the early 1980's they published the plurality of string theory papers, but their contribution declined swiftly after 1986, compensated by a spike in paper output from the United States during the first superstring revolution. From this we can conclude that the first superstring revolution significantly altered the geographical distribution of string theory researchers, securing the pre-eminence of the United States at the center of string theory research. Also of interest is the steady growth in the number of countries publishing a significant number of string theory papers as time goes on, indicating an increasing acceptance of string theory as a valid line of research.