What does Wave Function actually measure?

avito009
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From what I understand in laymans terms (Since I am a beginner).

In quantum mechanics, particles don’t have classical properties like “position” or “momentum”; rather, there is a wave function that assigns a (complex) number, called the “amplitude,” to each possible measurement outcome. The Born Rule is then very simple: it says that the probability of obtaining any possible measurement outcome is equal to the square of the corresponding amplitude. (The wave function is just the set of all the amplitudes.)

Born Rule:
latex.php?latex=%5Cmathrm%7BProbability%7D%28x%29+%3D+%7C%5Cmathrm%7Bamplitude%7D%28x%29%7C%5E2.png


Couldnt find any diagrams. Could anyone better explain this to me with diagrams?
 
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I'm not sure how it could be made any simpler. You want to find the probability that a measurement will find a particle at a given location, you calculate the value of the wave function at that location, square its magnitude (or equivalently, multiply it by its complex conjugate), and that's the probability you're looking for.

If this doesn't make sense to you, you'll have to study complex numbers more before you take on QM. Any introductory text on complex numbers will have a diagram that gives an intuitive picture of what is meant by the "magnitude" and "complex conjugate" of a number.
 
Its like probabilities, in fact along with observables it predicts the probabilities of observational outcomes. In that sense it doesn't measure anything.

It can be explained and in a quite deep way what's going on - but unfortunately it involves advanced math.

But just for reference here it is (see post 137):
https://www.physicsforums.com/threads/the-born-rule-in-many-worlds.763139/page-7

The following may also help:
http://www.scottaaronson.com/democritus/lec9.html

Thanks
Bill
 
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The wave function itself is a mathematical construct - you cannot "observe" a wave function (they're complex in the sense of complex numbers). What you can observe are the eigenvalues of wavefunctions for a given operator, which are used to represent all dynamical variables such as position, angular momentum, etc. Operators act on the wave functions to give you the values you can get when you do perform the measurement. The wave function itself doesn't really "measure" anything.
 
The topic is also highly misleading and possibly reflects the OP's lack of understanding. The wavefunction doesn't "measure" anything! Rather, it is supposed to contain the complete description of the system in question, very much like the equation of motion of a dynamical system in classical mechanics.

The common problem that I have seen with this is that people are trying to run before they learn how to crawl. This is one of the examples where learning classical mechanics first, and getting a feel for what a Lagrangian/Hamiltonian mechanics is in terms of the classical description of a system, may actually be quite beneficial in getting an insight into deciphering the mathematics of QM. Otherwise, one is dangling in mid-air with no lifeline to anything.

Zz.
 
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. Towards the end of the first lecture for the Qiskit Global Summer School 2025, Foundations of Quantum Mechanics, Olivia Lanes (Global Lead, Content and Education IBM) stated... Source: https://www.physicsforums.com/insights/quantum-entanglement-is-a-kinematic-fact-not-a-dynamical-effect/ by @RUTA
If we release an electron around a positively charged sphere, the initial state of electron is a linear combination of Hydrogen-like states. According to quantum mechanics, evolution of time would not change this initial state because the potential is time independent. However, classically we expect the electron to collide with the sphere. So, it seems that the quantum and classics predict different behaviours!

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