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This article gets the paper totally wrong. Learning that the uncertainty principle gives rise to phenomena that popular science calls "wave-particle" duality wa

This article gets the paper totally wrong. Learning that the uncertainty principle gives rise to phenomena that popular science calls "wave-particle" duality was taught to me in quantum 101. From the abstract: "This idea...upper bounds the sum of the interference visibility and the path distinguishability. Such wave-particle duality relations (WPDRs) are often thought to be conceptually inequivalent to Heisenberg's uncertainty principle, although this has been debated." I'm quite surprised that anyone would think that those relationships wouldn't be direct consequences of uncertainty. They are directly analogous to position and momenta quantities. "Here we show that WPDRs correspond precisely to a modern formulation of the uncertainty principle" No surprises here.

Osmium 12y ago
> Learning that the uncertainty principle gives rise to phenomena that popular science calls "wave-particle" duality was taught to me in quantum 101. Agreed, just to expand on that: The hand-wavey relationship between wave-particle duality and the uncertainty principle was taught to me like this... Imagine you have a sine wave. It has a well-defined momentum, p, given by its wavelength. However, since it's infinitely periodic in space, it has no well-defined position, x. Now consider a wave-packet[1]. This has a very well-defined position, given by the centre of the packet, but no well-defined wavelength/momentum. These are the limiting cases. The Heisenberg uncertainty principle, ΔpΔx >= ħ/2, just quantifies this relationship. If you try and measure x, the wavefunction ends up more 'packet-like' and you can no longer measure p as well, and if you try and measure p, the wavefunction ends up more 'wave-like' and you can no longer measure x as well. That's all there is to it. It's not exactly rigorous, but I don't think this explanation is too misleading either (though I'd be happy to learn otherwise!). [1] https://en.wikipedia.org/wiki/Wave_packet https://en.wikipedia.org/wiki/Wave_packet
- monochromatic 12y ago
  Just a minor correction, but a wave packet isn't the limiting case. Something that approaches a delta function is.
davorak 12y ago
> This article gets the paper totally wrong. Learning that the uncertainty principle gives rise to phenomena that popular science calls "wave-particle" duality was taught to me in quantum 101. This is how it was taught to peers and I as well. I do not remember ever reading about any debate or uncertainty on the issue either.
- niels_olson 12y ago
  Eisberg and Resnick's Quantum Physics has a nice discussion on the philosophical disagreement. 2nd Edition, page 79.
  - davorak 12y ago
    That ~1 page of text does not discuss a connection or difference between the wave/particle duality and the uncertainty principle. It does mention at least one standard interpretation and have several quotes from famous people however. If there was something specific you wanted me to pull from it you will have to point it out to me.
    - niels_olson 12y ago
      Yeah, they're not taking a stand so much as introducing the reader to the fact there is a disagreement. You'd have to chase down the original sources to get details.
      - davorak 12y ago
        My assertion is that ~page of text has no introduction to a difference or connection between the wave/particle duality and the uncertainty principle. So there are no sources to track down.
skywhopper 12y ago
I'm only a pop-physics fan (well, I did get a physics minor 20 years ago) but the fact that these were two sides of the same coin was always clear even to me. I always wonder if these sorts of misinterpretations are intentional hyping on the part of the scientists for naive science writers, or whether the reporters are just that confused about things. Reminds me of the neverending stream of stories about how biologists have "overturned Darwin" by uncovering details that prove just how amazingly right Darwin was.

Osmium 12y ago

> Learning that the uncertainty principle gives rise to phenomena that popular science calls "wave-particle" duality was taught to me in quantum 101. Agreed, just to expand on that: The hand-wavey relationship between wave-particle duality and the uncertainty principle was taught to me like this... Imagine you have a sine wave. It has a well-defined momentum, p, given by its wavelength. However, since it's infinitely periodic in space, it has no well-defined position, x. Now consider a wave-packet[1]. This has a very well-defined position, given by the centre of the packet, but no well-defined wavelength/momentum. These are the limiting cases. The Heisenberg uncertainty principle, ΔpΔx >= ħ/2, just quantifies this relationship. If you try and measure x, the wavefunction ends up more 'packet-like' and you can no longer measure p as well, and if you try and measure p, the wavefunction ends up more 'wave-like' and you can no longer measure x as well. That's all there is to it. It's not exactly rigorous, but I don't think this explanation is too misleading either (though I'd be happy to learn otherwise!). [1] https://en.wikipedia.org/wiki/Wave_packet https://en.wikipedia.org/wiki/Wave_packet

monochromatic 12y ago
Just a minor correction, but a wave packet isn't the limiting case. Something that approaches a delta function is.

davorak 12y ago

> This article gets the paper totally wrong. Learning that the uncertainty principle gives rise to phenomena that popular science calls "wave-particle" duality was taught to me in quantum 101. This is how it was taught to peers and I as well. I do not remember ever reading about any debate or uncertainty on the issue either.

niels_olson 12y ago
Eisberg and Resnick's Quantum Physics has a nice discussion on the philosophical disagreement. 2nd Edition, page 79.
- davorak 12y ago
  That ~1 page of text does not discuss a connection or difference between the wave/particle duality and the uncertainty principle. It does mention at least one standard interpretation and have several quotes from famous people however. If there was something specific you wanted me to pull from it you will have to point it out to me.
  - niels_olson 12y ago
    Yeah, they're not taking a stand so much as introducing the reader to the fact there is a disagreement. You'd have to chase down the original sources to get details.
    - davorak 12y ago
      My assertion is that ~page of text has no introduction to a difference or connection between the wave/particle duality and the uncertainty principle. So there are no sources to track down.

skywhopper 12y ago

I'm only a pop-physics fan (well, I did get a physics minor 20 years ago) but the fact that these were two sides of the same coin was always clear even to me. I always wonder if these sorts of misinterpretations are intentional hyping on the part of the scientists for naive science writers, or whether the reporters are just that confused about things. Reminds me of the neverending stream of stories about how biologists have "overturned Darwin" by uncovering details that prove just how amazingly right Darwin was.