> So, electromagnetic field would actually be mediated by excitons and pi-tons not photons? No. This discovery doesn't change how electromagnetism works. This

> So, electromagnetic field would actually be mediated by excitons and pi-tons not photons? No. This discovery doesn't change how electromagnetism works. This is a discovery a layer above electromagnetism. Quasi particles are a useful model, because you can use them more easily to explain stuff than through the fundamental forces. For example phonons (another quasi particle found in solid stat physics) explain heat transfer more easily than if you tried to solve all the wave equations from scratch. (I like to think of quasi particles as analogous to chairs, desks and other every-day objects: they don't follow separate laws of physics, so nothing fundamentally new, but talking about them instead of just wave functions of electrons and nuclei has a much greater explanatory power).