Natalie Wolchover writes: Neil Johnson used to study electrons as a buttoned-up professor of physics at the University of Oxford. Then, a decade ago, he decamped to the University of Miami — a young institution that he sees as unconstrained by rigid traditions or barriers between disciplines — and branched out. In recent years, the 55-year-old physicist has published research on financial markets, crowds, superconductivity, earthquake forecasting, light-matter interactions, bacterial photosynthesis, quantum information and computation, neuron firing patterns, heart attacks, tumor growth, contagion and urban disasters, not to mention his extensive body of work on terrorism and other forms of insurgent conflict.

Johnson models the extreme events and behaviors that can arise in complex systems. The author of two books on complexity, he has found that the same principles often apply, regardless of whether a system consists of interacting electrons, humans or anything else. After the terrorist attacks of Sept. 11, 2001, he began modeling extremism in human society. He had also spent time in Colombia during the war against the FARC guerrilla army, and grew up near London during the era of IRA bombings. “I started wondering what the patterns of attacks in the respective places might be telling us about how humans do terrorism,” he said. “Terrorism suddenly became, for me, an urgent problem that I might be able to help society understand, and perhaps even one day predict.”

The rise of ISIS has served as both an impetus and test case for Johnson’s models. Even more recently, he has begun using his models to study the growth of white nationalist groups in the United States.

Quanta Magazine caught up with Johnson to discuss his findings by phone in June, before he left to spend the summer working with collaborators in Bogota, Colombia. A condensed and edited version of that conversation, and a subsequent email exchange after the events in Charlottesville, follows. [Continue reading…]