Spin Glasses: Old and New Complexity

Spin glasses are disordered magnetic systems that exhibit a variety of properties that are characteristic of “complex systems”. After a brief review of the systems themselves, I will discuss how spin glass concepts have found use in and, in some cases, further advanced areas such as computer science, biology, and other fields: what one might term “old complexity”. I will then turn to a discussion of more recent concepts and ideas that have flowed from studies of spin glasses, and using these introduce a proposal for a kind of “new complexity”.