I had to do a bit of research in basic Quantum Computing, when reading about "spooky action at a distance" or entanglement I was intrigued, I though this could be used to transfer information over distances, this seems to be a common misconception, you can read this Forbes article by a Ph.D. astrophysicist to understand why it doesn't work in detail, but I found a helpful analogy. It goes like this.
The Entanglement shoe-box analogy
Assume you have a shoe-box, one of the shoes has been taken and placed at the end of the universe. When you open the shoe-box you observe you have the right shoe, that means the shoe at the other end of the universe is the left one(assuming a normal shoe box). This is how entanglement works. Changing the shoe in the shoe-box in any way has no effect on the shoe that's on the end of the universe, you see the shoe you get the information and that is it. In the article it's said that forcing a state (changing the shoe) would break the entanglement. It is also stated on entanglement that "You know something important about the sum of both states together", or in the shoe-box you know that it should contain both a left and right shoe(normally). :)
Top comments (2)
The general idea here is close, but we need to change a few things to bring this up to what we deal with in quantum systems. While it is true that we could think of two entangled qubits as a pair of shoes, the analogy doesn't fit super well, because they would be the same kind of shoe. The idea is that they are set to be identical in their state... so maybe two left shoes?
The key point you make is the important one however. We can only measure the entangled qubits (or shoes in the box). If we try to change its position in the box, the relationship breaks.
Another thing that is important to understand is that we are the ones deciding which shoes are a pair, and effectively "putting them in the box". But as the article and your analogy state, once we have established that quantum state, again, all we can do is measure.... "yep, two left shoes, still in the box, cool".
Thank you for your insight David, it's very cool that folks with expertise like you are on these platforms sharing your knowledge.
Yes, I believe that the things you pointed out are important, I will edit the article when I get some free time. In the meantime hopefully people see your comment after reading the article.