Electron mass density approaches infinity?

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Discussion Overview

The discussion revolves around the concept of electron mass density and whether it approaches infinity due to the electron being treated as a point particle. Participants explore implications of the uncertainty principle, the definitions of mass and charge density, and the interpretation of particle properties at the quantum level.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants suggest that the electron's classification as a point particle implies a near-infinite mass density.
  • Others argue that this is a simplification, pointing to the uncertainty principle which would imply a finite radius for the electron.
  • It is noted that "mass density" or "charge density" cannot be defined for a point particle, raising questions about the applicability of these concepts at the particle scale.
  • Some participants reference published measurements of electron charge densities and related theories, suggesting that these measurements lend credibility to the concepts of density in certain contexts.
  • There is a discussion about the potential confusion between the spread of a wave function and the intrinsic properties of a particle.

Areas of Agreement / Disagreement

Participants do not reach a consensus; multiple competing views remain regarding the definitions and implications of mass density for point particles, as well as the interpretation of quantum properties.

Contextual Notes

Limitations include the dependence on definitions of density, the unresolved nature of the radius of an electron, and the varying interpretations of wave functions versus particle properties.

Loren Booda
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The electron is traditionally considered a point particle with finite mass. Does this indicate that the electron might have near infinite mass density?
 
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no. its just a simplification. the uncertainty principle would cause it to have finite radius.
 
"Mass density" or "charge density" cannot be defined for a point particle.
 
I don't think anyone knows yet what is really going on there, but if nowadays' theories are correct, and all elementary parcticles are point parcticles, there is indeed no meaning to density in the parcticle scale, it's just our way to express the forces particles apply on each other on the macroscopic scale.
 
Last edited:
granpa said:
no. its just a simplification. the uncertainty principle would cause it to have finite radius.

That doesn't sound right to me. What would that radius be?
 
clem said:
"Mass density" or "charge density" cannot be defined for a point particle.
There are published measurements of electron charge densities. That means the theory has been accepted, don't you think ? There are published measurements of Wigner distributions for photons in cavities. Even for massive extreme relativistic systems, such as light quarks confined in hadrons, the concepts of "mass/energy density", "angular momentum density", or "force densities" do make sense.

For instance :
"Tomographic theory for obtaining Wigner distribution for an electron in uniform magnetic field"
Phys. Lett. A301 (2002) 153

"Direct Measurement of the Wigner Function of a One-Photon Fock State in a Cavity"
Phys. Rev. Lett. 89 (2002) 200402

"Generalized parton distributions and strong forces inside nucleons and nuclei"
Phys.Lett. B555 (2003) 57
 
Vanadium 50 said:
That doesn't sound right to me. What would that radius be?

I too don't know where he is going with this, but I believe he meant the "radios" of how far the particle can be
 
I think some people have confused the spread of a wave function with a property of a particle.
 

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