Eli5: Does a photon really act different by looking at it? How does it know it’s being observed?
In: 11
Observation in this case doesn’t really mean “A person perceives it.” Really it means: “The quantum system is perturbed by interaction with some other system.” When you think about it, what is observing something? Generally it means that we bounce light off of it, or use a magnetic field to interact with it, or use some sort of detector to interact with it.
When a quantum system interacts with another system there’s a tendency for the state of both systems to change. That’s the “observation causes a change” we’re really talking about.
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