Beschreibung:
<jats:p>Discovery of new particles is not usually associated with condensed matter physics, because, at one level, we already know all the particles that go into the Hamiltonian—namely, electrons and ions. But it is a most profound fact of nature—indeed the very reason why physics can make progress at many different levels—that strongly interacting particles reorganize themselves to become more weakly coupled particles of a new kind. Often they are simple bound states of the old particles. But sometimes they are fantastically complicated collective objects (for example, solitons) that nonetheless behave as legitimate particles, with well-defined charge, spin, statistics, and other properties we attribute to particles.</jats:p>