Re: Observable-Hermitian link

Ali Mansour wrote:
Dear Members;

According to one of the principles of QM, measurable
properties of physical systems (observables) are
represented by Hermitian operators. Is this a
two-sided link? That is, can we say, as Albert
(1992:p.41) in his Quantum Mechanics and Experience,
"any Hermitian operator on a given space will
invariably associated with some measurable property of
the physical system connected with that space"?

It is an incomplete link in either direction.
Most operators have no sensible measuring protocol,
and many real life measuring protocols measure so-called POVMs
(positive operator-valued measures) rather than Hermitian
operators.

Arnold Neumaier

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