"Symmetry is one of the great unifying themes in physics. From cosmology to and from to , symmetries determine which shapes, interactions, and evolutions occur in nature. Perhaps the most important aspect of symmetry in theories of physics, is the idea that the states of a system do not need to have the same symmetries as the theory that describes them. Such spontaneous breakdown of symmetries governs the dynamics of , the emergence of new particles and s, the rigidity of collective states of matter, and is one of the main ways emerges in a quantum world. The basic idea of spontaneous symmetry breaking is well known, and repeated in different ways throughout all fields of physics."