Introduction to {\it Quantum Matter}

Abstract

This paper records my opening remarks at Nobel Symposium 148, on Graphene and Quantum Matter, at Saltsj\"obaden, Sweden, in June 2010. After some broad comments on the quantum theory of matter as a frontier of physics, and some slightly more particular comments about re-quantization, I report on the universal geometry that arises in a refined discussion of quantum-mechanical level crossing.