The Heisenberg uncertainty principal says we cannot currently precisely measure position and momentum of a particle. So in principle and one day if we figure out how, or have more better sensitive technology, we could. How will this change quantum mechnics? It seems to me we would need to rewrite all of it since this principle is fundamental?

  • $\begingroup$ Possible duplicates: physics.stackexchange.com/q/24068/2451 , physics.stackexchange.com/q/114133/2451 and links therein. $\endgroup$ – Qmechanic Oct 5 '20 at 8:52
  • $\begingroup$ The laws of arithmetic say we cannot have an odd number that's divisible by 2. So in principle, if one day we develop better technology to produce such numbers, how will this change arithmetic? $\endgroup$ – WillO Oct 5 '20 at 9:49
  • $\begingroup$ I don't think that is a proper analogy. $\endgroup$ – max_fisics Oct 6 '20 at 0:16

It is actually incorrect when you use the word "currently". The laws of quantum physics state in no "uncertain" terms that position and momentum cannot be known simultaneously with arbitrary precision. Note that in this case I said "known" and not "measured" (this is true for other quantities like energy and time etc). And the reason why I say that is because a quantum particle literally does not possess these two attributes simultaneously.

So stating that they cannot be "measured simultaneously with arbitrary precision" is true, but not complete in this sense. Therefore, we would not need to change to the laws of quantum theory (at least not for this reason). No advancements in technology can ever defeat this principle. The equation

$\Delta x \Delta p > \frac{\hbar}{2}$

is a property of nature not a limitation of technology. You were right though, when you stated that "the uncertainty principle is fundamental to quantum theory", but more importantly it is fundamental to nature.

  • $\begingroup$ Thanks sir. This helps alots. $\endgroup$ – max_fisics Oct 5 '20 at 6:09

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