3 ms·

Thanks, > "Charlie would ask Bob to eat the pear" This seems to be the key part. So when they run experiments on this, a certain result can be forced? > "The

by nonbel 10y ago

Thanks, > "Charlie would ask Bob to eat the pear" This seems to be the key part. So when they run experiments on this, a certain result can be forced? > "The important part is that Bob does not leave the room with predetermined fruit." Right, is this aspect measured somehow or only inferred from the theory?

danbruc 10y ago
I tried to set this straight in my comment. Charlie does not get to choose the fruit, the fruit is chosen at random. I just allowed Charlie to make the choice to emphasize that the choice happens outside of the room. Had I just said the choice happens at random, then it would not be obvious why this random choice could not also be made in the room with Alice. But then we were back at Bob leaving the room with either an apple or a pear. Have I look at my other comment with coins in boxes [1], that picture captures the situation better and in a way that is not easily translated to fruits. [1] https://news.ycombinator.com/item?id=13981054 https://news.ycombinator.com/item?id=13981054
- beojan 10y ago
  > I just allowed Charlie to make the choice to emphasize that the choice happens outside of the room. The problem is that allowing Charlie to make the choice allows him to use entanglement to transmit information faster than the speed of light.
- nonbel 10y ago
  I think, as others have pointed out, these analogies just aren't perfect enough. Do you know where I can find a data source for one of these tests? I checked a few recent papers from wikipedia but they only reported (very high level) summary statistics.
stouset 10y ago
> This seems to be the key part. So when they run experiments on this, a certain result can be forced? No, a result can't be forced. The analogy being used isn't very close. I'm going to summarize an explanation used in (IIRC) The Elegant Universe that may be helpful. Mulder and Scully each get shipped a box that's entangled with the other's box. These boxes have three windows. You're allowed to open only one window, at which point you'll see a red or green light. These boxes further have the property that they're entangled: if Mulder and Scully open the same window, they'll see the same color. Mulder and Scully open the same window on each box, and sure enough, they see the same color. Mulder claims that it's spooky action at a distance, Scully claims that the boxes are simply preprogrammed with a preset color pattern: one of "red, red, green", "green, red, green", "red, red, red", and so on. Mulder thinks for a bit and devises an experiment. They now acquire a large number of these boxes, each paired with a box in the other's possession (and in such a way they can identify which of their two boxes correspond to one-another). They proceed to open doors randomly, recording the results. Now they compare notes. In the case where they both opened the same door on an entangled pair of boxes, they always get the same result. So far so good. But what happens when they look at the results as a whole? Well, Scully's theory was that these boxes are preprogrammed and the data we've collected falsifies this theory. The only possible patterns, ignoring specific color and order, are ones where two windows reveal the same color and one window reveals another color (any ordering of GGR or RRG) or where all three windows open to the same color (GGG or RRR). In the latter case, their results will obviously match 100% of the time. In the former case, 2/3 of the time their results will match 2/3 of the time (for 4/9ths) and 1/3 of the time their results will match 1/3 of the time (for an additional 1/9th), adding up to 5/9ths. So if Scully's theory is true, when opening doors at random, they should have recorded the same result at least 5/9ths of the time (more if some boxes are programmed with all windows revealing the same color). Unfortunately for Scully, their records show that their results matched exactly 50% of the time. No matter how complicated your "programmed" hidden variable theory is (pseudorandom generators with the same seed, etc.), it is fundamentally disproven if the observed match rate is less than 5/9ths. The simplest explanation that fits this experimental result is that both boxes choose to display a color truly randomly when a given window is opened, but they both arrive at the same random color when the same window is opened! Again, this statistical argument works against all hidden variable theories.

by nonbel 10y ago

danbruc 10y ago

I tried to set this straight in my comment. Charlie does not get to choose the fruit, the fruit is chosen at random. I just allowed Charlie to make the choice to emphasize that the choice happens outside of the room. Had I just said the choice happens at random, then it would not be obvious why this random choice could not also be made in the room with Alice. But then we were back at Bob leaving the room with either an apple or a pear. Have I look at my other comment with coins in boxes [1], that picture captures the situation better and in a way that is not easily translated to fruits. [1] https://news.ycombinator.com/item?id=13981054 https://news.ycombinator.com/item?id=13981054

beojan 10y ago
> I just allowed Charlie to make the choice to emphasize that the choice happens outside of the room. The problem is that allowing Charlie to make the choice allows him to use entanglement to transmit information faster than the speed of light.
nonbel 10y ago
I think, as others have pointed out, these analogies just aren't perfect enough. Do you know where I can find a data source for one of these tests? I checked a few recent papers from wikipedia but they only reported (very high level) summary statistics.

stouset 10y ago

> This seems to be the key part. So when they run experiments on this, a certain result can be forced? No, a result can't be forced. The analogy being used isn't very close. I'm going to summarize an explanation used in (IIRC) The Elegant Universe that may be helpful. Mulder and Scully each get shipped a box that's entangled with the other's box. These boxes have three windows. You're allowed to open only one window, at which point you'll see a red or green light. These boxes further have the property that they're entangled: if Mulder and Scully open the same window, they'll see the same color. Mulder and Scully open the same window on each box, and sure enough, they see the same color. Mulder claims that it's spooky action at a distance, Scully claims that the boxes are simply preprogrammed with a preset color pattern: one of "red, red, green", "green, red, green", "red, red, red", and so on. Mulder thinks for a bit and devises an experiment. They now acquire a large number of these boxes, each paired with a box in the other's possession (and in such a way they can identify which of their two boxes correspond to one-another). They proceed to open doors randomly, recording the results. Now they compare notes. In the case where they both opened the same door on an entangled pair of boxes, they always get the same result. So far so good. But what happens when they look at the results as a whole? Well, Scully's theory was that these boxes are preprogrammed and the data we've collected falsifies this theory. The only possible patterns, ignoring specific color and order, are ones where two windows reveal the same color and one window reveals another color (any ordering of GGR or RRG) or where all three windows open to the same color (GGG or RRR). In the latter case, their results will obviously match 100% of the time. In the former case, 2/3 of the time their results will match 2/3 of the time (for 4/9ths) and 1/3 of the time their results will match 1/3 of the time (for an additional 1/9th), adding up to 5/9ths. So if Scully's theory is true, when opening doors at random, they should have recorded the same result at least 5/9ths of the time (more if some boxes are programmed with all windows revealing the same color). Unfortunately for Scully, their records show that their results matched exactly 50% of the time. No matter how complicated your "programmed" hidden variable theory is (pseudorandom generators with the same seed, etc.), it is fundamentally disproven if the observed match rate is less than 5/9ths. The simplest explanation that fits this experimental result is that both boxes choose to display a color truly randomly when a given window is opened, but they both arrive at the same random color when the same window is opened! Again, this statistical argument works against all hidden variable theories.