The people at SLAC for a long time have been compiling “Topcites” data which includes various lists of the most heavily-cited papers in HEP. From 1997-2003 Mike Peskin each year would write something about the significance of the lists. I first wrote a blog post about one of these lists nearly 10 years ago, about the 2003 list (see here). The 2013 list has just appeared, with a blog entry here, and the lists available here.
I haven’t written much about these lists for the past few years, since there didn’t seem to be much new to say. By the 2005 list it was becoming clear that there was so little new happening in hep-th that the list was dominated by pre-2000 papers, specifically the early AdS/CFT papers, as well as papers about speculative large extra dimension scenarios. This pattern has continued to this day. If you think citations mean something, this data shows a collapse of HEP theory having taken place sometime around mid-1999. The last two theory papers that appear in the overall heavily-cited paper list are a Randall-Sundrum paper from June 1999 and Seiberg-Witten’s String theory and non-commutative geometry (which I suspect makes the cut because “non-commutative geometry” is in the title, so this gets referenced by lots people doing something with non-commutative geometry, even if it has little to do with this paper).
The dominance of this list and of hep-th by AdS/CFT papers is hard to exaggerate, with Maldacena’s paper long ago leaving behind every other theory paper ever written, on track to hit 10,000 citations sometime later this year. Just as “string theory” has become ill-defined, now “AdS/CFT” is starting to become ill-defined, with these 10,000 papers covering a huge variety of different things. In addition there’s a great deal of hype and ideology surrounding this subject, with an ex-Harvard faculty member and now world’s most prominent string theory blogger yesterday calling for the murder of anyone caught “talking about the AdS/CFT correspondence’s not being dependent on string/M-theory”. More positively, Matt Strassler has been writing a very long series of blog posts that appear to be aimed at sooner or later getting to AdS/CFT. He’s at number 8, but I fear at least a hundred or so would be needed to cover the subject. By the way, people who like carrying on a tedious rear-guard action in the string wars by arguing about string theory and AdS/CFT should do it at another blog.
To get more fine-grained information about what recent work is getting cited, see listings here by arXiv category. The listing here of papers cited by hep-th papers during 2013 is dominated by the old AdS/CFT papers, but more recent things that occur in the top 10 are ABJM from 2008 (3d version of AdS/CFT), a 2006 paper on entanglement entropy from AdS/CFT (now a hot topic), and a review paper on AdS/CMT.