Example
The family of translation operators
is a one-parameter unitary group of unitary operators; the infinitesimal generator of this family is an extension of the differential operator
defined on the space of complex-valued continuously differentiable functions of compact support on R. Thus
In other words, motion on the line is generated by the momentum operator.
Read more about this topic: Stone's Theorem On One-parameter Unitary Groups
Famous quotes containing the word example:
“Our intellect is not the most subtle, the most powerful, the most appropriate, instrument for revealing the truth. It is life that, little by little, example by example, permits us to see that what is most important to our heart, or to our mind, is learned not by reasoning but through other agencies. Then it is that the intellect, observing their superiority, abdicates its control to them upon reasoned grounds and agrees to become their collaborator and lackey.”
—Marcel Proust (1871–1922)