internal symmetry
121Nonimaging optics — (also called anidolic optics)[1][2] is the branch of optics concerned with the optimal transfer of light radiation between a source and a target. Unlike traditional imaging optics, the techniques involved do not attempt to form an image of the… …
122Identical particles — Statistical mechanics Thermodynamics · …
123Quantum field theory — In quantum field theory (QFT) the forces between particles are mediated by other particles. For instance, the electromagnetic force between two electrons is caused by an exchange of photons. But quantum field theory applies to all fundamental… …
124Particle physics and representation theory — There is a natural connection, first discovered by Eugene Wigner, between the properties of particles, the representation theory of Lie groups and Lie algebras, and the symmetries of the universe. According to it, the different states of an… …
125Cambrian explosion — The Cambrian explosion or Cambrian radiation was the seemingly rapid appearance of most major groups of complex animals around Ma|530, as evidenced by the fossil record. [http://www.ucmp.berkeley.edu/cambrian/camb.html The Cambrian Period] ]… …
126nervous system — Anat., Zool. 1. the system of nerves and nerve centers in an animal or human, including the brain, spinal cord, nerves, and ganglia. 2. a particular part of this system. Cf. autonomic nervous system, central nervous system, peripheral nervous… …
127Ctenophora — For the genus of crane flies, see Ctenophora (genus). Comb jellies Temporal range: Cambrian – Recent …
128Chirality — For other uses, see Chirality (disambiguation). Two enantiomers of a generic amino acid Chirality, pronounced //kaɪˈrælɪtiː// is a property of asymmetry important in several branches of science. The word chirality is derived from the …
