Let be a normed vector space. A unit vector in is a vector with norm of 1. Given a non-zero vector , we can normalize it to a unit vector in the same direction.
Classically, the space of states of a quantum-mechanical system is given by a Hilbert space . Often, it is desirable to consider only states of unit norm. One can view this as requiring that probabilities sum up to 1.
Last revised on September 6, 2016 at 11:29:36. See the history of this page for a list of all contributions to it.