Niels Bohr: “Don’t tell God what to do.”
Caveat: my limited knowledge and understanding of QM means I’m probably right and wrong at the same time. Until I collapse, of course.
Mathematics versus reality?
Q-wave function gives the probability distribution for quantum measurements. So it is not necessarily a physical wave; more like a “probability wave” that is purely mathematical. Poetry.
That doesn’t mean however it is cheap let alone “wrong”: it is the most successful predictive algorithm in physics and used everyday in engineering.
This fact, of being “a mere mathematical tool” with incredible predictive powers has always begged the question: what do these QM formalisms tell us about the nature of physical reality, independent from those probabilistic descriptions?
The search for an ontological (ontological = experience-independent and measurement-independent reality) interpretation of QM, is a battle that never has been really settled.
Supposedly, QM is just too weird for common sense to be able understand it. Just do the calc, it works! So who cares “why exactly”. That may be true, but it doesn’t mean that QM works in every domain of physics. Like the other successful theories, it has a limited domain of validity.
Main domains in physics are still disconnected, with little or no overlap. Especially the theory Gravity and QM are at odds, begging each other for an explanation, of each other.
What does a theory look like that goes beyond both? Efforts in String theory that uses (I believe) 11 dimensions tried string it all together, but has no added value other than the art of mathematics. No physical experiments have been devised to test (parts of) string theory. Which as a consequence also means that it brings no technological advancements either. It eventually becomes a RIP case.QM to Grav:
“But you can’t explain me at all, can you! You can’t even figure out how to talk to me, in what language. You are way too vague and “general”. A pompous generic monster claiming universal size and God-like applicability.
My prediction is you are in fact more quantum than you like to admit. You are just a mob of trilzillions gravitons, of mini-particles size Planck. I predict you are a quantized spacetime field made off the tiniest bosons that quantum mechanics allows for. A mob of clueless and faithful morons who dutifully allow for contrarian fermions to make a real difference in life. You are but background canvas on which the Universe unfolds while it expands.”
Grav to QM:
“Well, you have proved beyond reasonable doubt that you are simply unable to make any sense of me. Let’s start with that empirical fact. Your “reality” exists of invisible things; mathematical derivatives of a reality you have no direct access to. You are so autistic you are not even aware of what you are doing: confusing the mathematical with the real. The predictive powers of your theory do not change that fact. My reality is an everyday empirical and sensory fact of human life, while you will always just be a figment of the imagination I’m afraid. Yes, the imaginary can predict the real but that doesn’t make it less imaginary. Sorry kid.”
Measurement problem
Measuring something at the quantum level always means you disturb and change what you hope to measure. For instance, when you measure an electron for up- or down spin, after it is measured it will remain in the up or down state thereafter. This suggests that the not-yet measured “electron” is, in fact, not an electron at all, and emerges only as an observed value during local interaction when a measurement takes place at another point in spacetime. Nothing magically “collapsed”, nor was the unmeasured electron in a “superposition” being in any-or-all possible states at the same time.
What actually “travelled” from location a to b?