The modern trend for physicists to work on problems in finance and economics began in the early 1990s and has gained momentum ever since. In the past few years, however, this field of 'econophysics' has come in for some strong criticism. Physicists, critics say, have mostly just re-discovered things that others already knew, and failed to build any valuable theory with explanatory power.
Is it true? Has econophysics really degenerated into irrelevance?
Should I open a Facebook account or not? Which of the two presidential candidates should I vote for in an American federal election? Will I get infected or not in a disease epidemic? Under what conditions does my choice or opinion become the popular one? The answer to each of these questions depends not only on the individual in question, but also crucially on their social or physical contacts with other individuals. Formulating this observation mathematically in terms of both local-contact-based binary decision-making processes and the concept of social network structures has led to many simple paradigmatic models, such as the voter model and the susceptible-infected model, that scientists study in order to understand how behaviors, opinions, and infectious diseases spread among human populations.
What cultural and social processes determine the size and growth of the vocabulary of a natural language? Does such a vocabulary grow forever? From large text databases, such as the Google Ngram, that have become available only recently, researchers tease out new and systematic insights into these fundamental questions and develop a mathematical model with predictive power that describes vocabulary growth as a simple stochastic process.
A column in Scientific American by SFI Distinguished Professor Geoffrey West makes the case for a theory of complex systems. The availability of "big data" driven by the digital revolution creates an opportunity for scientists to ...