https://en.wikipedia.org/wiki/Bell_test_experiments
This article describes the various experiments over the years. I don't
remember where i foundthe factor of 10,000 'c' velocity that the hypothetical
interfering signal would have to travel atto interfere. Jim Bell
From: jim bell <[email protected]> From: Zenaan Harkness
<[email protected]>
On Fri, Aug 05, 2016 at 09:10:42AM -0600, Mirimir wrote:
...
> Here, from <http://www.scottaaronson.com/blog/?p=2464>:
> > The violation of the Bell inequality has a schizophrenic status in
> > physics. To many of the physicists I know, Nature’s violating the
> > Bell inequality is so trivial and obvious that it’s barely even
> > worth doing the experiment: if people had just understood and
> > believed Bohr and Heisenberg back in 1925, there would’ve been no
> > need for this whole tiresome discussion.
>Seriously, I am none the wiser and cannot yet make sense of what they
>are saying.
>China apparently is putting this experiment in space - are they winning
>a game on prediction of one particular bit with > 75% probability, and
>if so, can they run that game numerous times to get that probability
>close to 100%, and if so, can the random inputs to each side be made not
>random so that the result of the game is transmission of information?
>I cannot begin to answer any of these questions sorry...
I will explain what I think they are doing in the fiber-optic version of the
experiment,at least so nobody is permanently misled by my previous analogy.
Imagine a central location on earth, let's call it Location B. 20,500 meters
west of that is Location A, and 20,500 meters to the east of "B" is Location C.
There's anoptical fiber going from "A" to "B", and another optical fiber going
from "B" to "C".Two entangled photons are produced at Location B, then one is
launched into fiber going to "A", and the other photon is launched from "B"
into the fiber going to "C".
After about 100 microseconds later (since the speed of light in that fiber is
about 'c'/1.4584, where 1.4584 is the index of refraction of infrared in
silica, thus 205.5 meters /microsecond), those photons emerge from their
respective ends. Notnecessarily at the same time, because the length of the
fibers may not be quiteidentical. They do the detection at Location A, and
through prior arrangement theyschedule the detection at "C" a few nanoseconds
later, possibly adjusting the physical length of the fiber to get the timing
close to being correct.. Good synchronization could be achieved by
GPS-controlled clocks, or perhaps a third fiber being used to synchronize local
clocks at "A" and "C".
They first detect at "A", and then detect at "C". And they might reverse the
order, forcompleteness. But that's not the end:To determine that there has
been more than a 50% correlation of the measured spins, they haveto transmit
the type (angle) of measurement they make by ordinary optical fiber.
(Although,it wouldn't have to be on an optical fiber: It could be a USB memory
stick glued to theshell of a fast snail, I suppose. the important thing is
that the information eventually getsto the other side, not how fast it takes to
get there.)
The information eventually gets to the other end, and they do the
calculations andverify that SOMEHOW, the fact that a measurement at "A" somehow
affected themeasurement at "C". If they "schmoo plot" (meaning carefully
adjust, then plot on a graph) https://en.wikipedia.org/wiki/Shmoo , they can
determine how fast some affecting particle or signal would have to travel to
affect the receiver at the other end. Since the delay from Location "A" to
"Location "C" would be (100+100) = 200 microseconds in a fiber, it would be
200/1.4584 = 137.136 microseconds from location A to location C,by air. (or in
a vacuum, or by radio, etc.)
That figure I found from an article a few years ago, that said it would have to
travel at least 10,000x that of 'c' to affect the measurement, would require
that the delay is measured by:137.136 microseconds/10,000 = 13.7126
nanoseconds. If the measurement at "A" occurred only 13.7136 nanoseconds
before the measurement at "C", and yet there wasstill correlation, this shows
that a velocity of at least 10,000 'c' to affect the outcome at "C".
Therefore, I conclude that it would be easy to measure the minimum effective
speed of the
hypothetical interfering particle or wave. That particle or wave would have to
travel 41,000meters in less than 13.7 nanoseconds, to achieve that
interference. Time measurement to 1 nanosecond is easy, to 1 picosecond is
doable, and in fact measurement of time valuesfar less than 1 picosecond can be
accomplished.
Jim Bell
https://en.wikipedia.org/wiki/Bell_test_experiments
