There is finally a scientific way to determine the hottest scientific topics. Michael Banks, a PhD student at the MPI-Stuttgart, in a recent paper extended the Hirsch Index for ranking research topics in Physics. The h-b index is based on the number of published papers and citations for a given topic. The second metric, m, normalizes the h-b by the the number of years that papers on the topic have been published. An m>3 means that a topic is hot. Moreover, a large m number combined with an h-b>100 represents a topic that was popular in the past and still is today. Finally, a small m but large h-b reflects an older topic that was popular for many years but is now less so. The following is a list of the 10 hottest topics in Physics (as of 2006), based on a larger dataset from the original paper.
The original Hirsch's h-index is based on the number of times that papers by a particular scientist are cited. A scientist with a h-index of 10, will have published at least 10 papers that have received at least 10 citations each. Similarly, a topic with an h-b index of 10 means that there are at least 10 papers on that topic, each of which has been cited at least 10 times. Some topics have been around longer than others, so the second metric, m, normalizes the h-b by the the number of years that papers on the topic have been published. The resulting m number indicates how important a particular topic is today. Like the original h-index, the h-b index is calculated by searching the ISI Web of Science database for the topic and then sorting the results by the number of citations.