Comment on Don't look now
Wirlocke@lemmy.blahaj.zone 7 months agoHonestly physicists don’t actually know what measuring is either. We don’t know when exactly the system is considered “measured” in the chain of entanglement, this is called the Measurement Problem.
Answers range from “shut up don’t think about it” to “there’s an infinite amount of universes split from each other for each quantum event!”.
cynar@lemmy.world 7 months ago
We know how it works, we just don’t yet understand what is going on under the hood.
In short, quantum effects can be very obvious with small systems. The effects generally get averaged out over larger systems. A measurement inherently entangled your small system with a much larger system diluting the effect.
The blind spot is that we don’t know what a quantum state IS. We know the maths behind it, but not the underlying physics model. It’s likely to fall out when we unify quantum mechanics with general relativity, but we’ve been chipping at that for over 70 years now, with limited success.
pcalau12i@lemmygrad.ml 5 weeks ago
Why should we assume “there is something going on under the hood”? This is my problem with most “interpretations” of quantum mechanics. They are complex stories to try and “explain” quantum mechanics, like a whole branching multiverse, of which we have no evidence for.
It’s kind of like if someone wanted to come up with deep explanation to “explain” Einstein’s field equations and what is “going on under the hood”. Why should anything be “underneath” those equations? If we begin to speculate, we’re doing just tha,t speculation, and if we take any of that speculation seriously as in actually genuinely believe it, then we’ve left the realm of being a scientifically-minded rational thinker.
It is much simpler to just accept the equations at face-value, to accept quantum mechanics at face-value. “Measurement” is not in the theory anywhere, there is no rigorous formulation of what qualifies as a measurement. The state vector is reduced whenever a physical interaction occurs from the reference point of the systems participating in the interaction, but not for the systems not participating in it, in which the systems are then described as entangled with one another.
This is not an “interpretation” but me just explaining literally how the terminology and mathematics works. If we just accept this at face value there is no “measurement problem.” The only reason there is a “measurement problem” is because this contradicts with people’s basic intuitions: if we accept quantum mechanics at face value then we have to admit that whether or not properties of systems have well-defined values actually depends upon your reference point and is contingent on a physical interaction taking place.
Our basic intuition tells us that particles are autonomous entities floating around in space on their lonesome like little stones or billiard balls up until they collide with something, and so even if they are not interacting with anything at all they meaningfully can be said to “exist” with well-defined properties which should be the same properties for all reference points (i.e. the properties are absolute rather than relational). Quantum mechanics contradicts with this basic intuition so people think there must be something “wrong” with it, there must be something “under the hood” we don’t yet understand and only if we make the story more complicated or make a new discovery one day we’d “solve” the “problem.”
Einstein once said, God does not place dice, and Bohr rebutted with, stop telling God what to do. This is my response to people who believe in the “measurement problem.” Stop with your preconceptions on how reality should work. Quantum theory is our best theory of nature and there is currently no evidence it is going away any time soon, and it’s withstood the test of time for decades. We should stop waiting for the day it gets overturned and disappears and just accept this is genuinely how reality works, accept it at face-value and drop our preconceptions. We do not need any additional “stories” to explain it.