# Questions tagged [measurement-problem]

DO NOT USE THIS TAG just because your question involves measurements (either quantum or classical). The measurement problem asks how wave function collapse occurs during measurement in quantum mechanics, and how it can be reconciled with unitary evolution.

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### In quantum experiments are we measuring the quantum state of a system or are we measuring the effect of the measurement on the quantum state?

At the macro classical world, measurements in experiments when done correctly interfere very little with the state of the system under investigation. As an example a digital ohmmeter with very high ...
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### How to add markers to IR photographs

I'm using an IR camera to identify thermal patterns. The thermal images are similar to this [LINK] image. I'd like to add markers to the area being measured to determine dimensions and normalize the ...
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1 vote
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### Trouble understanding the math of the preferred basis problem

I've been trying to understand the preferred-basis problem in QM, specifally in the Everettian intepretation. To quote an answer to another question which discusses this: In my opinion, the situation ...
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1 vote
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### Is the uncertainity principle explained by disturbances or only by the Fourier picture?

Qualitatively, the tradeoff in uncertainty between two non-commuting observables $\hat{x}$ and $\hat{y}$, could be explained by... the Fourier picture where the more one variable is defined (i.e., ...
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1 vote
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### Why macroscopic bodies should exist as wavepacket?

Based on my understanding, we assume that the electrons, exist as wavepackets in the solids while deriving the transport equations for transistors, we create wavepackets out of momentum eigenstates ...
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### Have objective collapse theories been ruled out by recent experiments?

Have objective collapse theories been ruled out by recent experiments, such as the entanglement of macroscopic objects? (vibrating drumheads)
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### I don't understand Wigner's friend paradox

The Wigner's friend experiment goes like this: Say Wigner instructed his friend to perform Schrödinger's cat experiment in a laboratory while he work from home, his friend made the measurement and ...
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### Are quantum experiments superdeterministic? [closed]

Lately this recent video of Dr. Sabine Hossenfelder made me think if this theory deserves a serious review and has substantial ground. What are the rigorous arguments against this theory today? Please ...
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### How is quantum "measurement" actually done?

There is a lot of talk in the fundamentals of QM about "measurement" and "observation", but never much specificity in what is going on at a basic level. For example, an electron ...
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### Copenhagen interpetation applied to a video recording [duplicate]

I always get a little confused when it comes to the Copenhagen interpretation, and especially the fact that (for instance as per this article https://medium.com/science-and-philosophy/the-copenhagen-...
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### Can weak measurement principles of Quantum mechanics be used in similar questions in classical estimation problems?

This is a surface level question and I don't want to go into detail. Imagine an algorithm which when used with a sensor output gives the statistical moments of a variable in nature (for example mean ...
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### Spacetime of a quantum measurement

In a classical(or wave) picture, when we measure a doppler effect from a receding galaxy, we are working on two wave crests essentially. Therefore, there are two events in spacetime for such detection....
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### Any unique or unified definition of measurement in physics?

I have not found any unique or unified definition of measurement in physics, and it seems that there isn't one. What is a unique or unified definition of measurement in physics?
1 vote
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### Kochen-Specker theorem and measurement map in the formalism of QM

There is (or rather was) a famous debate between Born and Einstein about interpretational issues of Quantum Mechanics. In this debate Einstein was advocating the so called theory of hidden variables. ...
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### Does the particle interfere with itself, or the observer?

In the double slit experiment, the observer doesn't know which slit the photon went through so the wavefunction is modelled as going through both slits at once and thus there's interference on the ...
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Suppose that one could "flip" a coin, and that it settled onto a platform. For simplicity, let the coin processed with the nonzero angular momentum on $y$ axis only. To further simplify the ...