writes "Vibrations within a matrix of a crystal, or any other supercooled substance which exhibits crystal-like properties are produced by phonons. They are a type of Nambu-Goldstone boson. UC Berkeley physicists claim to have proven that by counting the number of bosons in a material, whether a solid crystal, a magnet, or a superfluid, this will describe and predict the behavior of the material in a supercooled state and where the symmetry can be spontaneously broken.
Credit: Haruki Watanabe/UC Berkeley."Link to Original Source