<story><title>Einstein&apos;s missed opportunity to rid us of &apos;spooky actions at a distance&apos;</title><url>https://sciencex.com/news/2020-10-einstein-opportunity-spooky-actions-distance.html</url></story><parent_chain><item><author>Toutouxc</author><text>The way I understand it, this is exactly the simplified (and incorrect) explanation.&lt;p&gt;Say SOMEONE ELSE puts the marbles in two envelopes and sends them to you and your friend in Australia. (it&amp;#x27;s someone else because we don&amp;#x27;t actually create the entangled particles, we just &amp;quot;get&amp;quot; them)&lt;p&gt;The marbles being red and blue (or both red or both blue, depending on what you&amp;#x27;re measuring) from the beginning would be a LOCAL hidden variable. It&amp;#x27;s local because it&amp;#x27;s been predetermined at the moment of creation and the marbles carry the property on themselves and it&amp;#x27;s hidden because you don&amp;#x27;t know how&amp;#x2F;why the person putting the marbles in those envelopes decided those colors and you can&amp;#x27;t see them until you open the envelope (measure the particle).&lt;p&gt;This way if you don&amp;#x27;t open your envelope, your friend&amp;#x27;s envelope contains a marble that&amp;#x27;s 50&amp;#x2F;50 red or blue and the color will be the predetermined one no matter what you do with your marble at home. So whatever decides the marble&amp;#x27;s color has nothing to do with your marble, it&amp;#x27;s local to the friend&amp;#x27;s one.&lt;p&gt;The actual measurements work differently. It&amp;#x27;s been experimentally proven many times that at the moment you look at your marble, the other marble&amp;#x27;s 50&amp;#x2F;50 probability of being red and blue shifts substantially to, for example 75&amp;#x2F;25. And that&amp;#x27;s without it having any way of knowing that you&amp;#x27;ve seen your marble.
So there are hidden variables that we don&amp;#x27;t understand, but they&amp;#x27;re not local. They somehow affect both marbles.&lt;p&gt;In real life there aren&amp;#x27;t only two colors and the probabilities aren&amp;#x27;t those nice numbers, but you get the principle.</text></item><item><author>andomar</author><text>Say you put a red marble and a blue marble in two envelopes. You randomly post one envelope to Australia.  One year later, you open the other envelope.  You now know the color of the marble in Australia.&lt;p&gt;What&amp;#x27;s the difference between this and quantum entanglement?</text></item></parent_chain><comment><author>wnoise</author><text>&amp;gt; The actual measurements work differently. It&amp;#x27;s been experimentally proven many times that at the moment you look at your marble, the other marble&amp;#x27;s 50&amp;#x2F;50 probability of being red and blue shifts substantially to, for example 75&amp;#x2F;25. And that&amp;#x27;s without it having any way of knowing that you&amp;#x27;ve seen your marble. So there are hidden variables that we don&amp;#x27;t understand, but they&amp;#x27;re not local. They somehow affect both marbles.&lt;p&gt;This is completely incorrect, to the point where what you were trying to correct was actually more accurate, though incomplete.&lt;p&gt;The usual setup is that for any given axis, each person always measures 50:50.  Measuring your own doesn&amp;#x27;t change the odds of the other.&lt;p&gt;Knowing the _results_ of your own does.  For the same axis, the correlation is exact.  For axes with an angle theta between them, we get a correlation of R ~ cos(theta&amp;#x2F;2).&lt;p&gt;The upshot is that there is no underlying (classical) probability distribution that can give rise to this that can explain things for all measurement axes.  This is sometimes glossed as &amp;quot;correlation without correlata&amp;quot;.</text></comment>
<story><title>Einstein&apos;s missed opportunity to rid us of &apos;spooky actions at a distance&apos;</title><url>https://sciencex.com/news/2020-10-einstein-opportunity-spooky-actions-distance.html</url></story><parent_chain><item><author>Toutouxc</author><text>The way I understand it, this is exactly the simplified (and incorrect) explanation.&lt;p&gt;Say SOMEONE ELSE puts the marbles in two envelopes and sends them to you and your friend in Australia. (it&amp;#x27;s someone else because we don&amp;#x27;t actually create the entangled particles, we just &amp;quot;get&amp;quot; them)&lt;p&gt;The marbles being red and blue (or both red or both blue, depending on what you&amp;#x27;re measuring) from the beginning would be a LOCAL hidden variable. It&amp;#x27;s local because it&amp;#x27;s been predetermined at the moment of creation and the marbles carry the property on themselves and it&amp;#x27;s hidden because you don&amp;#x27;t know how&amp;#x2F;why the person putting the marbles in those envelopes decided those colors and you can&amp;#x27;t see them until you open the envelope (measure the particle).&lt;p&gt;This way if you don&amp;#x27;t open your envelope, your friend&amp;#x27;s envelope contains a marble that&amp;#x27;s 50&amp;#x2F;50 red or blue and the color will be the predetermined one no matter what you do with your marble at home. So whatever decides the marble&amp;#x27;s color has nothing to do with your marble, it&amp;#x27;s local to the friend&amp;#x27;s one.&lt;p&gt;The actual measurements work differently. It&amp;#x27;s been experimentally proven many times that at the moment you look at your marble, the other marble&amp;#x27;s 50&amp;#x2F;50 probability of being red and blue shifts substantially to, for example 75&amp;#x2F;25. And that&amp;#x27;s without it having any way of knowing that you&amp;#x27;ve seen your marble.
So there are hidden variables that we don&amp;#x27;t understand, but they&amp;#x27;re not local. They somehow affect both marbles.&lt;p&gt;In real life there aren&amp;#x27;t only two colors and the probabilities aren&amp;#x27;t those nice numbers, but you get the principle.</text></item><item><author>andomar</author><text>Say you put a red marble and a blue marble in two envelopes. You randomly post one envelope to Australia.  One year later, you open the other envelope.  You now know the color of the marble in Australia.&lt;p&gt;What&amp;#x27;s the difference between this and quantum entanglement?</text></item></parent_chain><comment><author>jayd16</author><text>This explanation seems like it can&amp;#x27;t be correct and must be a simplification as well.  If this was measurable in a way that&amp;#x27;s described here you&amp;#x27;d be able to transmit information.&lt;p&gt;I always imagined the two &amp;quot;marbles&amp;quot; as possibly being two similar but differing clocks instead.  The clocks will align more or less often depending on how similarly they&amp;#x27;re set and how fast each run.  With this analogy you can come up with any distribution that fits your fancy.&lt;p&gt;Its probably a silly analogy but it lets me cling my notions of no spooky action.</text></comment>