On 7/5/2018 3:55 PM, [email protected] wrote:
On Thursday, July 5, 2018 at 2:03:46 PM UTC-6, Brent wrote:
On 7/5/2018 11:27 AM, [email protected] <javascript:> wrote:
On Wednesday, July 4, 2018 at 10:57:06 AM UTC-6, Brent wrote:
On 7/4/2018 1:57 AM, 'scerir' via Everything List wrote:
*No. I am asserting that the INTERPRETATION of the
superposition of states is wrong. Although I have asked
several times, no one here seems able to offer a plausible
justification for interpreting that a system in a
superposition of states, is physically in all states of the
superposition SIMULTANEOUSLY before the system is measured.
If we go back to those little pointing things, you will see
there exists an infinite uncountable set of basis vectors
for any vector in that linear vector space. For quantum
systems, there is no unique basis, and in many cases also
infinitely many bases, So IMO, the interpretation is not
justified. AG*
***SIMULTANEOUSLY*** was used by EPR in their paper, but
that did not have much meaning (operationally, physically).
Can we say that the observable, in a superposition state,
has a ***DEFINITE*** value between two measurements?
No - in general - we cannot say that.
It's in some definite state. But it may be a state for which
we have no measurement operator or don't intend to measure;
so we say it is in a superposition, meaning a superposition
of the eigenstates we're going to measure. So it does not
have one of the eigenvalues of our measurement.
Brent
*
*
*So for the radioactive source, the superposed state, Decayed +
Undecayed, does NOT imply the system is in both states
simultaneously? *
No, it is in a state that consists of Decayed+Undecayed. So in a
sense it is in both simulatnaeously. If you are sailing a heading
of 45deg you are on a definite heading. But you are simultaneously
traveling North and East. And if someone was watching you with a
radar that could only output "moving north" or "moving east" it
would oscillate between the two and you might call that a
superposition of north and east motion.
Brent
*I see. But as I have pointed out, there are uncountably many sets of
basis vectors that result in the same vector along the 45 deg
direction. Thus, it makes no sense to single out a particular basis
and claim it is _simultaneously_ in both. *
That's where you're wrong. It makes perfect sense if that's the only
basis you can measure in. That's why I gave the hypothetical example of
a radar that could only report motion as northward or eastward. In some
cases, like decayed our not-decayed, we don't have instruments to
measure the superposition state. In other cases like sliver atom spin
we can measure up/down or left/right or along any other axis.
*ISTM, this is the cause of many of the apparent paradoxes in QM such
as Schroedinger's cat, or a radioactive source which is decayed and
undecayed simultaneously. I have no objection using such a state to do
a calculation, but I think it's an error to further interpret a
superposition in terms of simultaneity of component states. What say
you? AG*
I say use what's convenient for calculation. Don't imagine your
calculation is the reality.
Brent
*Same for cat, Alive + Dead? Same for ( (Undecayed, Alive) +
(Decayed, Dead) ) for Schroedinger's composite system? If that's
the case, why would anyone think these states are in any way
paradoxical or contradictory? AG*
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