Editing Ambiguity (section)

=== Notations in quantum optics and quantum mechanics ===
It is common to define the [[coherent states]] in [[quantum optics]] with <math>~|\alpha\rangle~ </math> and states with fixed number of photons with {{nowrap|<math>~|n\rangle~</math>.}} Then, there is an "unwritten rule": the state is coherent if there are more Greek characters than Latin characters in the argument, and <math>n</math>-photon state if the Latin characters dominate. The ambiguity becomes even worse, if <math>~|x\rangle~</math> is used for the states with certain value of the coordinate, and <math>~|p\rangle~</math> means the state with certain value of the momentum, which may be used in books on [[quantum mechanics]]. Such ambiguities easily lead to confusions, especially if some normalized adimensional, [[dimensionless]] variables are used. Expression <math> |1\rangle </math> may mean a state with single photon, or the coherent state with mean amplitude equal to 1, or state with momentum equal to unity, and so on. The reader is supposed to guess from the context.