# Questions tagged [heisenberg-uncertainty-principle]

This tag is for Heisenberg's quantum mechanical uncertainty principle. DO NOT USE THIS TAG for uncertainty in a non-quantum measurement.

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### Heisenberg's Uncertainty Principle - finding uncertainty in wavelength

I am confused about this problem: I needed to find the uncertainty of a wavelength using Heisenberg's uncertainty principle. In the solution, they differentiated $λ=c/f$ with respect to frequency to ...
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### Can you help me clear up the double slit experiment?

So I know what happens in a double slit experiment and that if you put an observer, it changes the outcome of the experiment. It has to do with Heisenberg's uncertainty, but how does his uncertainty ...
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### Uncertainty Principle for a Particle on a Ring [duplicate]

In the case of a particle on a line, if I prepare an (although non-normalizable) eigenstate of the momentum so that the uncertainty in the measurement of the momentum vanishes, the uncertainty ...
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### Quantum state where uncertainty in kinetic energy is zero?

While reading Shankar's book on Quantum Mechanics, I encountered an interesting problem: Compute $\Delta T\cdot\Delta X$, where $T = P^2/2m$. I found several solutions online which arrive at the ...
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### Heisenberg's Uncertainty Principle about electrons [closed]

According to Heisenberg's Uncertainty Principle when we shoot or project photons on an electron from one side then there is 100% possibility that there is some error in calculating the position and ...
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### Uncertainty principle for a particle of known momentum

For a particle of known momentum we know the wave function. But why is that in that case we have uncertainty in momentum then according to uncertainty principle ∆x∆p>=h/2π? If so then uncertainty in ...
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### Can faster sampling frequency solve the x-ray diffraction phase problem?

In the x-ray diffraction, only the intensity the light that hits the detector is captured while the phase of the light is not determined. The energy flux of the light is the Poynting vector. For a ...
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### Heisenberg's Microscope and the Compton effect

https://www.youtube.com/watch?v=dgoA_jmGIcA&t=459s Hi, this is my first question on physics stack exchange. I'm in my second year in college and I'm currently learning quantum/nuclear physics. So ...
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### Doubt on application of uncertainty principle for an ion trap

Ion trap involves the application of an electromagnetic field to suspend and confine a charged particle. At the centre of this picture, you see a saddle shape. This means that the ions are pushed ...
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### Is this explanation for the uncertainty principle correct?

In a pre-print I read that "The position of the particle is indeterminate as it could be anywhere along the wave packet. Hence compressing the wave packet to reduce the indeterminacy in position will ...
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### Uncertainty principle in classical mechanics and quantum mechanics

I was just listening to the Leonard Susskind lectures on youtube on qunatum mechanics basics. He said that uncertainty principle in classical mechanics is completely different from that of quantum ...
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### Physical interpretation of eliminating the real component when deriving the uncertainty principle

I've been working on some quantum information theory problems and I've revisited Griffith's Quantum Mechanics. On page 109, he derives the uncertainty principle. He goes through the steps: For ...
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### Does wave-particle duality rely on accepting the Copenhagen interpretation?

If you're a scientist that subscribes to the many worlds theorem, does that mean you do not accept wave particle duality? Seeing as MW postulates that the wave or particle form has always existed that ...
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### What is exactly a quantum fluctuation?

According to the quantum fluctuation by Heisenberg Uncertainty Principle, matters and antimatters are created and disappearing by colliding in an almost complete vacuumed area of space near the event ...
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### In Bohmian mechanics, do electrons move inside an atom?

Look at http://www.bohmian-mechanics.net/whatisbm_pictures_hydrogen.html. It is mentioned that in the rest states of a bound electron, the position of the electron is stationary, since the ...
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### General commutation question

If I have three general observables, $\hat{C}$, $\hat{H}$, and $\hat{L}$, and the commutation relation between $\hat{C}$ and $\hat{H}$ is given by, $$[\hat{C}, \hat{H}] = \hbar \hat{L}$$ At the ...
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### By recombination ion/electron does predominataly the ground level form?

When an electron is near an ion and has small velocity it will be certainly captured and both form an atom. I think that the electron will predominantly release energy dE just the proper quantity ...
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### What would happen if the opposite complementary variables of two entangled particles were measured at the same time?

Many explanations about the uncertainty principle and its related EPR paradox state that it is impossible to measure opposite complementary variables on different entangled particles; for example, ...
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### Is polarization complementary along its different axes?

Is polarization complementary along its different axes -- much like the spin of a particle is -- thus implying that the uncertainty principle holds for polarization measurements on these different ...
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### What does the Heisenberg principle actually mean? [duplicate]

As far as I can understand, the Heisenberg principle limits the possibility of calculating the exact position and momentum of electrons, as the light we use to observe it changes it's velocity. But ...
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### Virtual pair of particle-antiparticles trajectory [duplicate]

Is it possible to do heuristic calculations on virtual pair of particle-antiparticle trajectories that appear in a vacuum? For example, what is the maximum distance between them during virtual process?...
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### Why doesn't detecting a photon's position after passing through a narrow slit violate HUP?

I understand that after passing through a narrow slit a photon's momentum is uncertain, however since its position can be inferred from having passed through the slit, a subsequent position ...
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### Does uncertainty principle truly represent the “lower bound” of the information we can obtained from a pair of noncommunicable operator?

Background I: Suppose the commonly used non commuting operator $\hat p$ and $\hat x$. The uncertainty principle told us that $\sigma_p\sigma_x\geq \frac{\hbar}{2}$. In standard quantum mechanic ...
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### Question about point particle vs. wave equation location

Another uncertainty question, this came up in another forum. As I understand it an electron, for example, is a point-like particle. I take this to mean it exhibits dimensionless properties, but ...
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### A basic question on Heisenberg uncertainty and experiment

I’m not a physicist or anything even close. But what I understand from the reason for the Heisenberg uncertainty is that the photon is changing the volecity/momentum when it hits the particle. ...
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### Uncertainty Principle for a locally constrained particle

According to the Uncertainty Principle we cannot calculate the precise position or momentum of a quantum particle at the same time, trying to calculate one of them would make the other uncertain. One ...
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### Why do neutron stars with more mass have smaller volume?

I know about Heisenberg uncertainty which makes more localized neutrons have a wider range of undefined momentum, and Pauli exclusion principle which prohibit neutrons from getting too close or "...