1

In this answer https://physics.stackexchange.com/a/9253/256311, the author said

Usually, we think of quantum mechanics to govern the microscopic world, involving length scales of under a micrometer, i.e. 10^−6 . Achieving quantum effects on a length scale of 100=10^5 means you span 11 orders of magnitude

My question is: Why do we care about the quantum mechanics scale? Say, two far-separated electrons approximately localized at $x$ and $y$, in system A and B, respectively. We care about how one electron entangle with another electron. Wow does length scale in each system matter? No matter how things going in System A, it has nothing to do with the distance between two systems.

Qmechanic
  • 220,844
Nicole
  • 21

1 Answers1

-1

Why do we care about the quantum mechanics scale?

Distance is no object for entangled particles. The connection between entangled particles is non-local and instantaneous, so distance does not matter. Where distance does matter is at very short distances. While at a large distance of perhaps 100 kilometers an error of one atom length is almost negligible, but at very short distances approaching the Planck length, the uncertainty in the position of two particles due to the Heisenberg uncertainty principle becomes very significant. This is one reason why classical physics does not describe interactions at very short distance scales.

KDP
  • 10,288