Modes of Collaboration in Modern Science - Beyond Power Laws and Preferential Attachment

The goal of the study is to determine the underlying processes leading to the observed collaborator distribution in modern scientific fields, with special attention to non-power law behavior. Nanoscience is used as a case study of a modern interdisciplinary field, and its coauthorship network for 2000-04 period is constructed from NanoBank database. We find three collaboration modes that correspond to three distinct ranges in the distribution of collaborators: (1) for authors with fewer than 20 collaborators (the majority) preferential attachment does not hold and they form a log-normal "hook" instead of a power law, (2) authors with more than 20 collaborators benefit from preferential attachment and form a power law tail, and (3) authors with between 250 and 800 collaborators are more frequent than expected because of the hyperauthorship practices in certain subfields.