“it’s not fair! you altered the result by measuring it!”
I don’t understand the exact mechanic on why observing (not as in watching per se) collapses the function and gets you a result; why?
“it’s not fair! you altered the result by measuring it!”
I don’t understand the exact mechanic on why observing (not as in watching per se) collapses the function and gets you a result; why?
Comments
The problem is that quantum mechanics runs on probability, not deterministic mathematics. With regular physics, like, with say, a guy throwing a ball, or whatever, you can write an equation that predicts the path of the ball at its position at every moment in time that will be correct. With quantum physics, it just doesn’t work this way. We have wave functions that predict the path of particles, but they don’t tell us exactly where the particle will be at any moment in time, rather, they give us a probability function that says where the particle is more or less likely to be. We don’t know where the particle will actually be with certainty until we detect it in a particular place.
This is very weird and annoying, and but physicists mathematically ‘solved’ for this uncertainty with the concept of superposition. Okay, they say, let’s just pretend that the particle is in every possible position it could be in and mathematically model that, and then we’ll say that when we observe the particle in a particular place the wave function ‘collapses’ and effectively chooses which of the many different answers we came up with is correct. Weirdly, this works, and yields predictions that are experimentally validated, despite making no logical sense to our human brains at all.
Because the only way to observe, at that level, is to interact. Bounce particles off of one another or make fields wobble one another. Under carefully controlled circumstances the interactions can be kept in a quantum state too, but any information that escapes into the wider world is of a collapsed state.
I’m most impressed by the delayed choice quantum eraser experiment, which seemingly retroactively decides whether quantum information about another already recorded particle has gotten out or stayed inside.