How do you explain the Heisenberg uncertainty principle?

In summary: So to determine the position of an object you can scatter light off of it. Fine. But then my textbook says you can't know the exact position of the object because of diffraction effects. We've covered the diffraction of light through narrow slits but I don't know why if you were scattering light off a ball or an electron or something that it would end up diffracted.In summary, the HUP states that because of diffraction effects, it is impossible to know the exact position of an object.
  • #1
hamsa0
11
0
So to determine the position of an object you can scatter light off of it. Fine. But then my textbook says you can't know the exact position of the object because of diffraction effects. We've covered the diffraction of light through narrow slits but I don't know why if you were scattering light off a ball or an electron or something that it would end up diffracted.
 
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  • #2
hamsa0 said:
So to determine the position of an object you can scatter light off of it. Fine. But then my textbook says you can't know the exact position of the object because of diffraction effects. We've covered the diffraction of light through narrow slits but I don't know why if you were scattering light off a ball or an electron or something that it would end up diffracted.

The HUP has nothing to do with macro sized objects such as a billiard ball, it has to do with sub-atomic particle, which are a whole 'nother story.
 
  • #3
K well since I haven't studied this so called whole 'nother story of diffraction by subatomic particles, I'll just have to believe everyone that there is in fact diffraction that causes uncertainty in the position. Thanks.
 
  • #4
hamsa0 said:
K well since I haven't studied this so called whole 'nother story of diffraction by subatomic particles, I'll just have to believe everyone that there is in fact diffraction that causes uncertainty in the position. Thanks.

I don't think diffraction has anything to do with what happens at the subatomic level in the sense of the uncertainty that the HUP describes, it is a matter of quantum uncertainty.
 
  • #5
One finds explanations relating the HUP to experiments quite frequently, but this is misleading. The HUP restricts the "existence" of sharp values, not only measurement accuracy in certain experiments. It is a rather simple mathematical excercise to derive the HUP for two non-commuting observables w/o every talking about experiments.

We had this discussion here a couple of times.
 
  • #6
hamsa0 said:
So to determine the position of an object you can scatter light off of it. Fine. But then my textbook says you can't know the exact position of the object because of diffraction effects. We've covered the diffraction of light through narrow slits but I don't know why if you were scattering light off a ball or an electron or something that it would end up diffracted.

The HUP that randomness/uncertainty is a fundamental of existence. It has been observed for elementary particles such as photons, electrons (and some bigger atoms?) etc. yet.
 
  • #7
phinds said:
I don't think diffraction has anything to do with what happens at the subatomic level in the sense of the uncertainty that the HUP describes, it is a matter of quantum uncertainty.
I think that it have connection.
HUP is a consequence that Fourier distribution of location is distribution of momentum. (And oppositely) But, both momentum and location are sinusoidaly distributed. Similarly as diffraction...
But, you Hamsa describes Heisenberg microscope. It is good one for visualisation of HUP, but it is not the same thing. Heisenberg microscope contains hidden variables which are not existent according to tests of Bell equation.
 
  • #8
In my opinion, diffraction causes uncertainty is because of degree of angular resolution. But it is pretty much on bigger object rather than particles decribed by quantum, like cells displayed by light microscopes. While talking about quantum, it deals with single photons. Photons with different wavelength act differently with electrons that causes different degree of uncertainty. Just my personal understanding.
 
  • #9
ZealScience said:
In my opinion, diffraction causes uncertainty is because of degree of angular resolution. But it is pretty much on bigger object rather than particles decribed by quantum, like cells displayed by light microscopes. While talking about quantum, it deals with single photons. Photons with different wavelength act differently with electrons that causes different degree of uncertainty. Just my personal understanding.

No. The HUP is inherent to ALL quantum particles, not just photons.

I've described previously how the single-slit diffraction is a clear manifestation of the HUP.

https://www.physicsforums.com/showthread.php?t=394171

Note that one can get the diffraction effects from photons, electrons, protons, neutrons, buckyballs, etc.

Zz.
 

Related to How do you explain the Heisenberg uncertainty principle?

What is the Heisenberg uncertainty principle?

The Heisenberg uncertainty principle is a fundamental principle in quantum mechanics that states that it is impossible to know both the precise position and momentum of a particle at the same time. In other words, the more accurately we know the position of a particle, the less we know about its momentum, and vice versa.

Who developed the Heisenberg uncertainty principle?

The Heisenberg uncertainty principle was developed by German physicist Werner Heisenberg in 1927.

What is the significance of the Heisenberg uncertainty principle?

The Heisenberg uncertainty principle is significant because it fundamentally challenges our understanding of the physical world and the concept of determinism. It also has important implications for the measurement and observation of particles at the microscopic level.

How is the Heisenberg uncertainty principle related to the wave-particle duality?

The Heisenberg uncertainty principle is closely related to the wave-particle duality of quantum particles. This duality states that particles can exhibit both wave-like and particle-like behaviors, and the uncertainty principle helps to explain this phenomenon by showing that the more we know about a particle's position, the less we know about its wave-like properties and vice versa.

Can the Heisenberg uncertainty principle be violated?

No, the Heisenberg uncertainty principle is a fundamental principle in physics and cannot be violated. It has been extensively tested and verified through various experiments, and any apparent violations are due to measurement errors or limitations in our technology.

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