# Physical properties of a particle in Bohmian mechanics

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Are the physical properties of a particle spread out through the wave function in bohmian mechanics?
This is from wikipedia
"Also, unlike in classical mechanics, physical properties (e.g., mass, charge) are spread out over the wavefunction in de Broglie–Bohm theory, not localized at the position of the particle.[9][10]"
If this is true, then how come we always detect particle properties as points?

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PeterDonis
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Are the physical properties of a particle spread out through the wave function in bohmian mechanics?
I don't think this question has a well-defined meaning.

This is from wikipedia
What article? Please give a link. Also, Wikipedia is not a good source by itself, particularly for a subject like this; you need to look at a textbook or peer-reviewed paper (and the Wikipedia article might give references to these).

how come we always detect particle properties as points?
We don't. First, a particle's properties, like mass or charge, aren't the same as the particle itself. Second, we never actually detect a particle at a precise point; the best we can do is to detect it within some small region of space.

Demystifier
Demystifier
Gold Member
"Also, unlike in classical mechanics, physical properties (e.g., mass, charge) are spread out over the wavefunction in de Broglie–Bohm theory, not localized at the position of the particle.[9][10]"
That's true.

If this is true, then how come we always detect particle properties as points?
Because we detect positions, not charges and masses. Have you ever seen the mass of your body? No, but you have seen the position of the needle on your weight scale, as in this picture
https://livehealthyosu.com/2011/08/25/dairy-plus-or-minus/weight-scale/

That's true.

Because we detect positions, not charges and masses. Have you ever seen the mass of your body? No, but you have seen the position of the needle on your weight scale, as in this picture
https://livehealthyosu.com/2011/08/25/dairy-plus-or-minus/weight-scale/
But what about bubble chambers and cloud chambers? Don't they shows charged particles as point charges with no charge spread out?
https://www.scientificamerican.com/article/electron-spherical-electric-dipole-moment/
When we measure electrons we see them as point charges with a cloud of photons around them, its like a sphere.
I don't think we would get these results if particles in bohmian mechanics had their charge spread out at all times, right?

Nugatory
Mentor
But what about bubble chambers and cloud chambers? Don't they shows charged particles as point charges with no charge spread out?
They do not - they show a succession of single-point position measurements. If you google for "Mott Problem" you will find much good stuff including Sir Nevill Mott's 1929 paper which substantially resolved the quantum mechanical treatment of cloud and bubble chambers.

(As you might infer from the date, the appearance of tracks in cloud and bubble chambers was a problem for collapse interpretations as well as the Bohmian mechanics of this thread - the initial wavefunction is spherically symmetrical, so where does this linear track come from?)