  In this work, we study the correlation between interdisciplinarity of papers
within physical sciences and their citations by using meta data of articles
published in American Physical Society's Physical Review journals between 1985
to 2012. We use the Weitzman diversity index to measure the diversity of papers
and authors, exploiting the hierarchical structure of PACS (Physics and
Astronomy Classification Scheme) codes. We find that the fraction of authors
with high diversity is increasing with time, where as the fraction of least
diversity are decreasing, and moderate diversity authors have higher tendency
to switch over to other diversity groups. The diversity index of papers is
correlated with the citations they received in a given time period from their
publication year. Papers with lower and higher end of diversity index receive
lesser citations than the moderate diversity papers.
