In the same way that life, itself, is an emergent phenomena in biology, so too are many fascinating condensed matter systems. The big examples are ferromagnetism, and superconductivity. In ferromagnetism, upon application of a magnetic field to a ferromangetic material, all spin domains align, and retain their magnetisation even when the field is switched off! This is spontaneous symmetry breaking in action! In a superconductor, when cooled to below the superconducting critical temperature, current flows without any resistance!
I'll be making a post exclusively on ferromagnetism, tomorrow, continuing our ongoing series. You can read the latest post on paramagnetism, here, in the mean time.
The key idea of emergence in condensed matter is characterised by complex ensembles of particles behaving in dramatically different ways to their microscopic constituents. I thoroughly enjoyed this talk by Edward Witten, so much so, that I felt compelled so share it with the community, here.
