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+--- Thread: A guide to (not) understanding quantum mechanics (leave it at magic or not?) (/thread-13663.html)
A guide to (not) understanding quantum mechanics (leave it at magic or not?) - C C - Feb 15, 2023
https://arstechnica.com/science/2023/02/a-guide-to-not-understanding-quantum-mechanics/
EXCERPT: Yet despite its overwhelming success as a framework for understanding what nature does, quantum mechanics tells us very little about how nature works. Quantum mechanics provides a powerful set of tools for successfully making predictions about what subatomic particles will do, but the theory itself is relatively silent about how those subatomic particles actually go about their lives.
For example, take the familiar concept of a quantum jump. An electron in an atom changes energy levels and thus either absorbs or emits energy in the form of one photon of radiation. No big deal, right? But how does the electron “jump” from one energy level to another? If it moves smoothly, like literally everything else in the Universe, we would see the energy involved change smoothly as well. But we don’t.
So does the electron magically disappear from one energy level and magically reappear in another? If it does, name one other physical object in the Universe that acts like that. While you’re at it, please give me a physical description of the unfolding of this magic act. I'll wait.
Quantum mechanics is completely silent on how the electron changes orbitals; it just blandly states that it does and tells us what outcomes to expect when that happens.
How are we supposed to wrap our heads around that? How can we possibly come to grips with a theory that doesn’t explain how anything works? People have struggled with these questions ever since quantum mechanics was developed, and they’ve come up with a number of ways to make sense of the processes involved in quantum behavior. Let’s explore three of these interpretations of quantum mechanics to see if any of them satisfy our cravings for a "why" behind all this odd phenomenology... (MORE - details)
COVERED: The Copenhagen interpretation ... The many-worlds interpretation ... Lost in the multiverse ... The pilot-wave interpretation
RELATED (scivillage): The weirdness of quantum mechanics forces scientists to confront philosophy
RE: A guide to (not) understanding quantum mechanics (leave it at magic or not?) - Kornee - Feb 16, 2023
Quote:
"For example, take the familiar concept of a quantum jump. An electron in an atom changes energy levels and thus either absorbs or emits energy in the form of one photon of radiation. No big deal, right? But how does the electron “jump” from one energy level to another? If it moves smoothly, like literally everything else in the Universe, we would see the energy involved change smoothly as well. But we don’t."
Turns out things are not quite as mysterious as made out:
https://www.quantamagazine.org/quantum-leaps-long-assumed-to-be-instantaneous-take-time-20190605/
RE: A guide to (not) understanding quantum mechanics (leave it at magic or not?) - confused2 - Feb 17, 2023
Kornee Wrote:Turns out things are not quite as mysterious as made out:
https://www.quantamagazine.org/quantum-l...-20190605/
I'm not sure superposition states are exactly 'normal'.
Seems like having a window into the Schrodinger cat box and seeing the cat go from (say) 10% probability of being a dead cat to dead or not.
If you had 10 cats and 10 boxes and you stopped (reversed) the experiment at the 10% probability of being dead could you get all 10 cats out alive every time? Repeat at 90% chance of being dead (sorry cats) ..?
RE: A guide to (not) understanding quantum mechanics (leave it at magic or not?) - Kornee - Feb 17, 2023
(Feb 17, 2023 12:42 PM)confused2 Wrote: I'm not sure superposition states are exactly 'normal'.The cat itself is always either dead or alive (although death is never instantaneous for cyanide poisoning). What hypothetically could be caught and reversed is the nuclear decay event triggering the Geiger counter etc.
Seems like having a window into the Schrodinger cat box and seeing the cat go from (say) 10% probability of being a dead cat to dead or not.
If you had 10 cats and 10 boxes and you stopped (reversed) the experiment at the 10% probability of being dead could you get all 10 cats out alive every time? Repeat at 90% chance of being dead (sorry cats) ..?
However afaik no-one expects to ever have the kind of control there the team had with their multi-level superconducting 'atom'.
RE: A guide to (not) understanding quantum mechanics (leave it at magic or not?) - confused2 - Feb 17, 2023
There's a quantum zeno effect where you keep measuring the cats (or whatever) and the thing that would happen if you didn't keep measuring doesn't happen. I guess there must be some element of pulling an event back from the brink .. or even over the brink .. involved.
https://en.m.wikipedia.org/wiki/Quantum_Zeno_effect