Question about entanglement

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CWatters - 29 May 2007 11:03 GMT

Novice here..

Is it possible to entangle two objects in such a way that when untangled the
mass of one is different to the other? In other words the mass is
equal/undefined until untangled?

I'm guessing not - as this would seem to imply problems for conservation of
momentum or ??

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PD - 29 May 2007 18:39 GMT

On May 29, 5:03 am, "CWatters"
<colin.watt...@turnersNOSPAMoak.plus.com> wrote:

> Novice here..
>
[quoted text clipped - 4 lines]
> I'm guessing not - as this would seem to imply problems for conservation of
> momentum or ??

Hmmm... I'm not sure I agree with your last assertion/guess.
After all, the K-long and K-short are entangled states of two
different mass eigenstates.

PD

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CWatters - 30 May 2007 08:43 GMT

> On May 29, 5:03 am, "CWatters"
> <colin.watt...@turnersNOSPAMoak.plus.com> wrote:
[quoted text clipped - 10 lines]
> After all, the K-long and K-short are entangled states of two
> different mass eigenstates.

I'll have to look up what an eigenstate is - long time since I heard that
term.

I was thinking...Say you are able to split "something" into to two entangled
objects, then seperate them by some distance and examine them. Presumably
there would be reaction forces as the objects were seperated. Would the two
forces be identical? If not then it would appear you have gained information
as to which object is going to be more massive when untangled. If they are
the same then how can the objects untangle themselves into different masses?
Wouldn't that you had moved mass without a reaction force.

I must be making a mistake.

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PD - 30 May 2007 15:52 GMT

On May 30, 2:43 am, "CWatters"
<colin.watt...@turnersNOSPAMoak.plus.com> wrote:

> > On May 29, 5:03 am, "CWatters"
> > <colin.watt...@turnersNOSPAMoak.plus.com> wrote:
[quoted text clipped - 25 lines]
>
> I must be making a mistake.

Perhaps. I believe the problem is the application of an interaction to
the particles in the entangled state, which would *automatically*
collapse the entangled wave function. The entangled two-particle state
exists precisely by virtue of not performing individual measurements
on the particles in the state. See Feynman's description of the two-
slit experiment in The Character of Physical Law.

PD

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CWatters - 31 May 2007 00:15 GMT

> > > Hmmm... I'm not sure I agree with your last assertion/guess.
> > > After all, the K-long and K-short are entangled states of two
[quoted text clipped - 19 lines]
> on the particles in the state. See Feynman's description of the two-
> slit experiment in The Character of Physical Law.

Yeah I recall that peeking in the box kills the cat or not. So we can't tell
a K-long from a K-short until they collapse.

So if you could somehow liberate a K-long and a K-short from a bit of
matter, what happens to that remaining bit? Does it experience a reaction
force and move off in the opposite direction? I guess the answer must be
that the remaining bit of matter is also entangled with the L-long and short
so that trying to measure which way it moves also collapses the lot?

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PD - 31 May 2007 03:48 GMT

On May 30, 6:15 pm, "CWatters"
<colin.watt...@turnersNOSPAMoak.plus.com> wrote:

> > > > Hmmm... I'm not sure I agree with your last assertion/guess.
>
[quoted text clipped - 36 lines]
> that the remaining bit of matter is also entangled with the L-long and short
> so that trying to measure which way it moves also collapses the lot?

Yes, I believe that's right.

PD

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Edward Green - 30 May 2007 17:54 GMT

On May 30, 3:43 am, "CWatters"
<colin.watt...@turnersNOSPAMoak.plus.com> wrote:

> > On May 29, 5:03 am, "CWatters"
> > <colin.watt...@turnersNOSPAMoak.plus.com> wrote:
[quoted text clipped - 15 lines]
> I'll have to look up what an eigenstate is - long time
> since I heard that term.

That is going to make it hard to say anything meaningful about
entanglement, since the definition involves eigenstates.

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Natural Science Forum / Physics / General Physics / May 2007

Question about entanglement