- #36
PeterDonis
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What do you mean by "right now"?VECT said:-How many different observables for particles are there right now?
Observables are things that can potentially be measured. There are theoretically an infinite number of them, but none of them are "right now", they're just observables.
Sort of. The obvious conjugate observable would be time (energy <-> time by analogy with momentum <-> position), but time is not an observable in QM. (We are talking about non-relativistic QM here; quantum field theory, which is what you need to do relativistic QM, is a different thing with its own set of issues.) However, it turns out that there is a way to relate the uncertainty in energy to something associated with time: roughly speaking, the "time uncertainty" ##\Delta t## of a system is the expected time for the system to undergo a significant change, and this ##\Delta t## has the kind of uncertainty relation with ##\Delta E##, the uncertainty in energy, that you would expect: ##\Delta E \Delta t \ge \hbar##.VECT said:Is the Energy observable also subject to some sort of uncertainty principle?
However, none of that even matters unless you are measuring the energy, and measuring the energy of a molecule means interacting with it and potentially disrupting it. See below.
No, measuring the energy observable can disrupt molecular stability, because measurement is an interaction. But if a molecule is just sitting there, not being measured, there is no "variation in the energy observable". See further comments below.VECT said:Given that variation in the Energy observable theoretically disrupt molecular stability
You seem to be thinking of a quantum system that is just sitting there, like a molecule, as having continuous "variation" in "observables". That's not correct. A quantum system that is just sitting there is just sitting there. To see any "variation" you have to measure it. More precisely, to see any variation in a particular observable, you have to conduct a measurement of that observable on a large number of identically prepared quantum systems and then do statistics on the results. "Variation of an observable" isn't even a concept that makes sense for a single quantum system.VECT said:what potential theoretical macro disruptions (if any) can be caused by variations in these other observables?