Do scientists trace hot topics?

Abstract

Do scientists follow hot topics in their scientific investigations? In this paper, by performing analysis to papers published in the American Physical Society (APS) Physical Review journals, it is found that papers are more likely to be attracted by hot fields, where the hotness of a field is measured by the number of papers belonging to the field. This indicates that scientists generally do follow hot topics. However, there are qualitative differences among scientists from various countries, among research works regarding different number of authors, different number of affiliations and different number of references. These observations could be valuable for policy makers when deciding research funding and also for individual researchers when searching for scientific projects.

Figure 1. Empirical preferential attachment to hot fields of new papers in the PR-PACS data set.

(a) The cumulative probability functions κ(k) in the years 2000 and 2008. Inset: the distribution function of the sizes of fields. (b) The exponents α for different years. We start our measurements from 1995, not 1976, the beginning year of the data, since the method requires a relatively large initial system. Notice α = 0.52–0.87 is near the lower end of all the exponents collected in Table I. The 2009 exponent is relatively smaller compared to its previous several years for reason that we do not yet know. If not mentioned, Δt is one year in this paper. The straight lines are guide to the eye through this paper.

Figure 2. Results for authors from the most-contributed countries in the PR-PACS data set.

(a) The cumulative probability functions κ(k) in the year 2008 for USA, Germany, Japan and P. R. China. The exponent of Chinese authors (α = 1.06) is much larger than that of other countries. Inset: The exponents α for different years, where the exponents α of China always are larger than that of USA. (b) The relative contribution ratio R^c(k) for USA, Germany, Japan and P. R. China.

Figure 3. The preferential attachment exponents α with respect to the number of authors N_Aut (the number of affiliations N_Aff in the inset) in the year 2000 and 2008.

Note that every three numbers for authors are grouped together and labelled as the intermediate number, e.g., 1, 2 and 3 are grouped together and labelled as 2. Overall, the exponents α increase with number of authors and affiliations.

Figure 4. The preferential attachment exponents α with respect to the number of references N_Ref.

Clearly, the exponents α increase with the number of references. The absolute value of α is a bit larger in recent years than in early years for larger number of references.