Entangled Particles ``` Name: Filip Status: educator Grade: 12+ Country: USA Date: Winter 2012-2013 ``` Question: This question is about entangled particles. Can it be that the only "wire" connecting entangled particles that that is gravity? That the big bang caused entangled particles that were close to each other to expand. Because the big bang is not an explosion, but a space-time expansion. Replies: Entangled particles are a quantum mechanical phenomenon, not really related to the big bang, or gravity. It is more closely related to laws of quantum mechanics that deal with the symmetry of particle pairs. Over simplified, these symmetry laws demand that if one of a pair of particles has a “spin” that is UP, its partner must have a “spin” that is DOWN. So if I measure the UP spin of one particle, the spin of the other particle must be DOWN, in order to conserve the symmetry of the pair – no matter how far apart the particles are. Now be aware that I am cheating on you a bit because I have not told you what “spin” is, and I have not told you what UP and DOWN are and how they are measured. That gets very complicated both the physics and the math. A rough analogy – very rough – is a coin with a “head” and a “tail”. If I toss the coin and observe the “head” I know, without any further observation, that the hidden side must be a “tail”, without turning the coin over to observe the other side. The whole phenomenon of particle entanglement is theoretically involved, as well as experimentally difficult to measure. Vince Calder Hi Filip, Thanks for the question. Based on my knowledge of quantum theory (at the graduate level), the "wire" that connects two entangled particles is actually the wave function of the two particles. I remember several chalk-boards of derivations regarding entangled particles and there was no mention of gravity. I hope this helps. Please let me know if you have any further questions and I will have to dust off my notes. Thanks Jeff Grell Click here to return to the Physics Archives

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