Point particle of point charges cannot be maintained in an equilibrium configuration solely by the electrostatic interaction of the charges. In quantum mechanics, there is a distinction between an elementary particle (also called "point particle") and a composite particle. An elementary particle, such as an electron, quark, or photon, is a particle with no internal structure. Whereas a composite particle, such as a proton or neutron, has an internal structure (see figure). However, neither elementary nor composite particles are spatially localized, because of the Heisenberg uncertainty principle. The particle wavepacket always occupies a nonzero volume. For example, see atomic orbital: The electron
Emmy (given name) Emmy (given name) Emmy is a feminine (sometimes also masculine) given name. Orthographic variants include Emme, Emmi and Emmie. The name is in many instances a hypocoristic of either Emma (itself being in origin a hypocoristic of a number of ancient Germanic names beginning in "ermen") or (more rarely) Emily, or Emmanuel (Emmanuelle). It came to be used as a separate (rare) German name, given officially in Germany from the later 19th century. As an officially given feminine name, Emmy ranked 66th in Sweden and 89th in France as of 2010. Emmy is rarely also encountered as a surname. Notable