# Re: Can someone explain why this doesn't work?

`On Fri, Jul 26, 2013 at 10:52 AM, John Clark <johnkcl...@gmail.com> wrote:`
```
> On Thu, Jul 25, 2013 at 6:21 PM, meekerdb <meeke...@verizon.net> wrote:
>
>  > I think this misunderstands Jason's thought experiment.  I think he's
>> assuming the source is polarized at 0deg, the same as A, not a random
>> source as you assume.
>>
>
> The photon has no polarization at all unless a filter is involved
> somewhere.
>

There are 3 filters in my thought experiment.

> My filter can be orientated at any angle, in this case it just happens to
> be 0 degrees. When it hits the filter only 2 things can happen, the photon
> goes through the filter or it does not. The probability of the
> undifferentiated photon going through the filter or being stopped by it is
> 50 50 and I have no way of changing that probability. If the photon goes
> through my filter set at 0 degrees then the photon was always polarized at
> exactly 0 degrees and so was its entangled brother photon a billion light
> years away even if the two were created a billion years ago. If the photon
> does NOT get through my filter set at 0 degrees then the photon was always
> polarized at exactly 90 degrees and so was its entangled brother photon a
> billion light years away even if the two were created a billion years ago.
>

Sure.  But here is where it gets interesting.  If a photon passes a filter
orientated at 0 degrees, then it encounters a filter at 90 degrees it will
be blocked.  But, if you insert a filter in the middle orientated at 45
degrees then there is a 50% chance it will continue through that filter
after passing the 0 degree filter, and also a 50% chance that that photon
will also pass the filter at 90 degrees.  Therefore there is a 25% chance a
photon that passes the filter at 0 degrees passes the next 2 filters.

My question is: if you do this experiment with entangled photons, and send
one photon through the filter at 0 degrees, and it passes, then you send
the twin photon through a filter at 45 degrees, and it passes, then is
there now a chance the first photon will now pass a filter at 90 degrees?
(when otherwise it would not have, save for the twin photon passing the
filter at 45 degrees)

>
> Remember that I could have picked any angle to set my filter at, I picked
> angle X for no particular reason and did so only 30 seconds ago, but my
> choice today means that my photon and its entangled brother a billion light
> years away have always been polarized at  X degrees or at X + 90 degrees.
> So I have made the number X special to both photons regardless of if my
> photon gets through my filter or not, even though both photons were created
> a billion years before I was born. You can't use this for faster than light
> communication but I still find it very weird.
>
>
If the experiment I described does not work (which I do not believe it can
but I am not sure how it fails, perhaps photons are always blocked at the
filter at 90 degrees), then that shows there really isn't anything spooky
going on at all.

> > He's proposing that inserting B will cause A to transmit some photons
>> (~25%) that go thru C.  Removing B will result in no photons passing thru
>> C.  So removing and replacing B can send dots and dashes to someone just
>> beyond C.
>>
>
> If my differentiated photon with a known polarization encounters a filter
> that its brother photon has not then the delicate quantum entanglement
> between the two is destroyed and there are just 2 unrelated photons a
> billion light years away.
>

I don't think that is correct.  If a photon passes a 0 degree filter, the
twin photon a billion light years away will always be stopped by a 90
degree filter.

Jason

--
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