Uncertainty

Metadata
aliases: [Uncertainty in quantum mechanics]
shorthands: {}
created: 2021-12-11 12:52:02
modified: 2022-01-10 04:13:04

If is a self-adjoint operator on a Hilbert space and is a unit vector in , let denote the standard deviation associated with measurements of in the state , which is computed as

We refer to as the uncertainty of in the state .

For a single observable , it is possible to choose so that is as small as we like, but for two observables, if they do not commute, their uncertainties cannot be made arbitrarily small simultaneously.