natural unit | has definition Unit of length, time, mass, etc. in which the fundamental constants c (the speed of light), h bar (Planck's constant) and kB (Boltzmann's constant) are equal to unity. That is, c, h bar and kB have the numerical value 1. (For example, if we measure length in light-years and time in years, then c = 1 light-year per year.) The use of natural units allows these constants to be omitted from mathematical equations, leading to less-cluttered calculations. In natural units, E = mc2 becomes E = m and E = kBT becomes E = T, so that both mass and temperature can be expressed in units of energy. (Of course, the correct factors of c, h bar and kB must be inserted at the end of a calculation to obtain measurable quantities.) | ![has source: Coughlan, G.D., Dodd, J.E. 1999 The Ideas of Particle Physics, Cambridge University Press, 2001-09-27 09:32:55.0 has source: Coughlan, G.D., Dodd, J.E. 1999 The Ideas of Particle Physics, Cambridge University Press, 2001-09-27 09:32:55.0](facet.gif) |