Hacker News new | ask | show | jobs
by swashbuck1r 3296 days ago
[I'm not a physicist] I like your analogy for color entanglement. However, it doesn't show the "weirdness" of superposition (the balls don't have a concrete value until one of the boxes are opened, at which point, this triggers the determination of the open box's color value), nor the "spookiness" of action-at-a-distance (opening one box instantly influences the state of the ball in the other box -- which now must be the opposite color when its box is opened).

Intuitively, someone might think: well, the ball colors were "decided" while the two balls were next to each other (ballA will be orange, ballB will be purple), and the information about the color is attached to the balls, so the balls know what color to be when they are separated and later opened (they have "hidden variables" indicating the assigned color)....however, the reality (provable statistically by Bell's Theorem) is that the balls do not carry this color information, and instead the act of opening the box, randomly sets the color of BallA and instantly affects the color that BallB will have.

So if both people synchronize the time to open the box (that has some time relativity problems), so that BoxA is opened a fraction of a second before BoxB, then BoxA's color will influence BoxB's color (seen a fraction of a second later), but that will have happened faster than the speed of light would allow if BoxA was sharing its color information with BoxB.

1 comments

> the balls don't have a concrete value until one of the boxes are opened,

> opening one box instantly influences the state of the ball in the other box

How do you know that without opening the box?

This analogy is confusing because it is incorrect in some fundamental ways. You aren't just opening a box and seeing one or the other color. The measurement itself determines a role in the outcome that you couldn't predict in advance.

It is more like you get to choose to measure only one of the red, green or blue channels. If you send a message containing which channel and the measurement, the other person can do the same measurement and find the complementary value. Without the channel and the original measurement the other person just sees random behavior.

The spooky part is that I don't choose the color channel to measure until after the entangled balls are separated

Bohr and Heisenberg interpret it that way.

https://en.m.wikipedia.org/wiki/Copenhagen_interpretation

And Schrödinger's cat never told us what really happened inside the box :)

https://en.m.wikipedia.org/wiki/Schrödinger%27s_cat