Xiao-Gang Wen
A quantitative change can lead to a qualitative change. The system with many degrees of freedom can demonstrate qualitatively new phenomena. This introductory chapter summarizes the principle of emergence, which states that the properties of material are mainly determined by the organizations (or the orders) of atoms in the material. The different organizations of microscopic degrees of freedom not only give rise to traditional symmetry breaking orders (such as crystal, magnets, superfluids, etc), they also give rise to new topological/quantum orders (such as fractional quantum Hall states, superconductors, etc). Those different orders lead to the rich properties of materials and phenomena that we see every day. The collective excitations in the new topologically ordered states can even be gauge bosons and fermions that satisfy Coulomb's law. So the principle of emergence in many-body systems may explain the origin of light and electrons, as well as the beauty in laws of physics.
Oxford University Press eBooks•Sep 6, 2007•0 citations