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.
It knows that it’s being observed because it has to interact with the detector. So, when photon interacts with the detector they change their behavior.
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.
Imagine a billiard table is a field, and billiard balls are photons. The only manner you have of detecting photons is by hitting the cue ball. If you hear the strike of cue ball on billiard ball, you have detected a photon. And the photon’s trajectory has been affected.
It knows that it’s being observed because it has to interact with the detector. So, when photon interacts with the detector they change their behavior.
It knows that it’s being observed because it has to interact with the detector. So, when photon interacts with the detector they change their behavior.
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.
The only photons you “see” are the ones that hit your retina and have their energy absorbed. All those photons zipping by in front of you, but missing your eyes, you don’t even know about.
Imagine a billiard table is a field, and billiard balls are photons. The only manner you have of detecting photons is by hitting the cue ball. If you hear the strike of cue ball on billiard ball, you have detected a photon. And the photon’s trajectory has been affected.
Imagine a billiard table is a field, and billiard balls are photons. The only manner you have of detecting photons is by hitting the cue ball. If you hear the strike of cue ball on billiard ball, you have detected a photon. And the photon’s trajectory has been affected.
Latest Answers