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Many of the users here may know "Astrid," the name given to the first isolated ion. It is a Barium ion. So a quantum particle is not an illusion. It has an objective reality. It has a finite mass and finite dimension. Its photo is attached below.

Now see Heisenberg's quote:

The invisible elementary particle of modern physics does not have the property of occupying space any more than it has properties like color and solidity. Fundamentally, it is not a material structure in space and time but only a symbol that allows the laws of nature to be expressed in especially simple form.

Even though above picture is not of elementary particles, Astrid is definitely a quantum particle. In other words, any theoretical physicist would apply quantum mechanics to study it, and not classical mechanics. So

  • Is Heisenberg's quote no longer valid?, or

  • Is Heisenberg's quote still a fact of life?

innisfree
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atom
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1 Answers1

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The photograph was taken by Hans Dehmelt in 1974. Anyone interested in the work of Hans Dehmelt should read his Nobel lecture available here.

Re your question about Heisenberg's quote: the quote doesn't apply because this is a picture of an ion not an elementary particle. The ion has a physical size courtesy of being a bound state of many elementary particles. The elementary particles themselves are rather more elusive objects.

You should also note that this is not an image of a barium ion. It is the light scattered from a barium ion. The ion itself is far too small to produce an optical image. The resolution of the photograph is around a micron and the ion itself is 10,000 times smaller than this.

Community
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John Rennie
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  • Fisrt thing: Elementary particles are not elusive, but illusive, according to Heisenberg. There is difference between words elusive and illusive. Second thing: then the barium ion which is made of these illusive particles must be also illusive. If something is illusive, how can light scatter from it ? – atom Dec 21 '15 at 03:46