Talk:No-teleportation theorem

correction
I changed the first paragraph. It originally stated: " no-teleportation theorem states that quantum information cannot be measured with complete accuracy", but this is obviously wrong since quantum information can, in fact, be measured with complete accuracy in the sense described on this very same page! Strictly speaking, quantum information is not the same thing as quantum state. If we encode quantum information into the state of, say, photons in a certain way we can in principle later recover it without any errors. Also, if the state we would like to measure belongs to a known set of orthogonal states then we can, in principle, measure it with perfect accuracy.88.148.223.130 (talk) 19:46, 13 February 2013 (UTC)

Strange first sentence
''In quantum information theory, the no-teleportation theorem states that an arbitrary quantum state cannot be measured with complete accuracy.

This appears to be a vague restatement of the Heisenberg uncertainty principle, without any numbers or definition of concepts.

Maybe there's some content to the article (or do I mean the result?), other than relabelling of nomenclature to sound important? Even "Heisenberg, but implemented on a computer!" would make it patentworthy (and intriguing to a sympathetic reader) if it were explained with a bit of concrete technical detail.178.38.97.233 (talk) 00:38, 2 May 2015 (UTC)


 * I just reworded it to remove multiple awkward sentences. 67.198.37.16 (talk) 19:12, 23 September 2015 (UTC)

First sentence still strange
An arbitrary state of a qbit is $$ \alpha |+\rangle +\beta |-\rangle$$ which can clearly be expressed classically by giving the numbers $$\alpha,\beta$$ What is rather meant is that an unknown state can not be fully known by measurement, and the classical results of the measurement cannot completely characterise the state. The unknown is important, since it is means that the measurement cannot be tailored to the known state. — Preceding unsigned comment added by 75.155.165.57 (talk) 19:26, 30 January 2022 (UTC)