Condensed Matter Physics
Most phases of matter can be understood through the lens of spontaneous symmetry-breaking. For example, crystals are periodic arrays of atoms that are not invariant under all translations (only under a small sub-set of translations by a lattice vector). Magnets have north and south poles that are oriented in a specific direction, breaking rotational symmetry. In addition to these examples, there are a whole host of other symmetry-breaking phases of matter including nematic phases of liquid crystals, charge- and spin- density waves, superfluids and many others.
There are several known examples of matter that cannot be described by spontaneous symmetry breaking, including: topologically ordered phases of matter like fractional quantum Hall liquids, and spin-liquids. These states do not break any symmetry, but are distinct phases of matter. Unlike the case of spontaneous symmetry breaking, there is not a general framework for describing such states.
Read more about this topic: Spontaneous Symmetry Breaking, Spontaneous Symmetry Breaking in Physics
Famous quotes containing the words condensed, matter and/or physics:
“If you read only the best, you will have no need of reading the other books, because the latter are nothing but a rehash of the best and the oldest. To read Shakespeare, Plato, Dante, Milton, Spenser, Chaucer, and their compeers in prose, is to read in condensed form what all others have diluted.”
—Anna C. Brackett (1836–1911)
“But, though light-headed man forget,
Remembering Matter pays her debt:
Still, through her motes and masses, draw
Electric thrills and ties of Law,
Which bind the strengths of Nature wild
To the conscience of the child.”
—Ralph Waldo Emerson (1803–1882)
“Although philosophers generally believe in laws and deny causes, explanatory practice in physics is just the reverse.”
—Nancy Cartwright (b. 1945)