Undergrad HUP and the observer effect

[DesertFox]

TL;DR

At the end of the day, aren't they the same?

The observer effect results from the interaction of a quantum system with a measurement device.

The HUP is more fundamental: it results from the fact that certain quantum measurements cannot be made simultaneously (or, equivalently: certain quantum observables do not commute, most famously - position and momentum).

The relevant wikipedia article says: "Historically, the uncertainty principle has been confused with a related effect in physics, called the observer effect, which notes that measurements of certain systems cannot be made without affecting the system, that is, without changing something in a system."

So, as far as I understand, the HUP is not observer effect. And that's held by the majority of scientists.

How do we know that they are different?Is there an experimental proof or it's all about math? Does the proof depend on the quantum interpretation which is applied?

Any explications of the topic will be appreciated!

 

[PeterDonis]

How do we know that they are different?

Because the uncertainty principle is not a restriction on measurements or a property of measurements (although it is often misleadingly presented that way). It's a restriction on states. For example, the position-momentum uncertainty principle sets a limit on the possible states of a quantum system: there cannot be a state with position and momentum probability profiles that are more precise than the uncertainty principle allows.

 

[PeroK]

How do we know that they are different?Is there an experimental proof or it's all about math?

Technically, IMO, the HUP is a statistical law derived mathematically from the theory of QM. It doesn't directly limit the precision with which (almost) simultaneous measurements of position and momentum may be made. That's not what it says, despite the common misconception to the contrary.

Experimentally, there are many ways you can try to outwit the HUP. Einstein and Bohr had a famous running debate on this where Einstein would come up with a thought experiment that seemingly outwitted the HUP; and Bohr would refute it.

In general, the HUP (and indeed the more general UP for other observables like spin) manifests itself in a specific way in each experimental set-up. This is where it is subtler than something like Newton's third law. You could invent an unlimited number of scenarios and ask how Newton's third law applies and the answer is similar in each case. Whereas, the limitations on nature's behaviour imposed by the UP are much subtler, deeper and varied. And, indeed, this can be seen as an essential foundation of the physical behaviour required to produce a complex universe.

In other words, without the UP, nature would be too simple to produce chemistry or anything interesting.