Events in Physics
Physics Colloquium
[Abstract]
In the famous words of Sir Arthur Eddington, 鈥淲e used to think that if we knew one, we knew two, because one and one are two. We are finding that we must learn a great deal more about 鈥榓nd鈥�.鈥� This pithy quotation captures the essence of the problem of complexity in physics. In many cases, even when we know the microscopic ingredients of a system, predictions of the behaviour of the entire system do not seem to follow easily from this knowledge.
In this talk, I shall try to explain why not. I shall draw on various examples from physics where strong correlations produce surprising effects, including traffic flow and traffic jams, the interiors of neutron stars, and electrical transport in nearly magnetic metals. I shall discuss Phil Anderson鈥檚 famous 1972 article 鈥淢ore Is Different鈥� – which does not say what many people say it says – and whether the advent of increasingly high-performance computing should change our view on some of these questions of emergence and explanation.
The talk is intended to be self-contained, and accessible to the interested amateur – all welcome!