On 6/23/2018 10:05 PM, Bruce Kellett wrote:
From: *Brent Meeker* <meeke...@verizon.net <mailto:meeke...@verizon.net>>
Of course in theory any pure state can be taken to be a basis vector
and there is an operator for which that state is an eigenvector, i.e.
a basis in which it is not a superposition. But in practice we don't
know what that basis is and in general we cannot physically realize
the corresponding operator. That's why a photon passing thru Young's
slits is said to be in a superposition of passing thru slit 1 and
passing thru slit 2. We know how to create an operator that measures
"passing thru slit 1" and we know how to create an operator that
measures "passing thru slit 2", but we don't know how to construct an
operator that measures "passes thru both slit 1 and slit 2". We can
write down the wf in the basis of "passing thru slit 1" and "passing
thru slit 2" and it's a coherent sum, i.e. a superposition of those
two. Decoherence theory says that we can't construct an instrument
which will measure "passes thru both slit 1 and slit 2" because such
an instrument would quickly decohere into one of the two stable
states "passed thru 1" or "passed thru 2" and the interference
pattern would not form (in repeated trials).
I am glad that you seem to have finally got the point of the basis
problem, Brent.
Yeah, I understood we were talking past one another. You were
considering changing to a different basis of measurement, not just
expressing a measurement in a different basis.
Brent
--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.
