hidden symmetry

Throughout the 1950s, theorists tried to construct field theories for the nuclear forces that would exhibit the same kind of gauge symmetry inherent in James Clerk Maxwell’s theory of electrodynamics and in QED. There were two major problems, which were in fact related.…

The continuous rotational symmetry of empty space is broken, and only a discrete symmetry exists. Broken rotational symmetry influences many important properties of crystals. Their resistance to compression, for example, may vary according to the direction along which one squeezes the crystal. Transparent crystals, such as quartz, may…