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Copernicus
2017-Oct-10, 12:17 PM
The following article states the electron is round as far as we can tell due to the electric dipole moment. I am wondering if the same answer could be obtained from other perfectly symmetrical shapes?

https://phys.org/news/2017-10-jila-method-electron.html

cjameshuff
2017-Oct-10, 12:27 PM
The following article states the electron is round as far as we can tell due to the electric dipole moment. I am wondering if the same answer could be obtained from other perfectly symmetrical shapes?

https://phys.org/news/2017-10-jila-method-electron.html

Could you provide some examples of other shapes that have spherical symmetry?

Copernicus
2017-Oct-10, 12:40 PM
Could you provide some examples of other shapes that have spherical symmetry?

Lets say you had a cuboctahedron shape, but as the hypothetical electron's many gazillion hypothetical components, are traveling through the cuboctahedron structure the electrons average x, y, and z direction were constantly changing direction resulting in an overall spherical shape.

see link for cuboctahedron sphere packing. https://www.google.com/search?q=cuboctahedron+sphere&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjawNvnh-bWAhUHsVQKHS9IBBwQ_AUICigB&biw=1093&bih=510#imgrc=JPdxU5Cn3YkZiM:

grant hutchison
2017-Oct-10, 01:52 PM
Lets say you had a cuboctahedron shape, but as the hypothetical electron's many gazillion hypothetical components, are traveling through the cuboctahedron structure the electrons average x, y, and z direction were constantly changing direction resulting in an overall spherical shape.So what about this is actually cuboctahedral in shape? What you describe sounds spherical.

Grant Hutchison

01101001
2017-Oct-10, 01:58 PM
Lets say you had a cuboctahedron shape, but as the hypothetical electron's many gazillion hypothetical components, are traveling through the cuboctahedron structure [...]

Hypothetically, let's say I didn't. You show me your hypotheses and I'll show you mine. Components? You mean the virtual-particles and their cloud?


[...] the electrons average x, y, and z direction were constantly changing direction resulting in an overall spherical shape.

The electron's directions? The directions were changing directions? And when the electron's directions change direction then that changes the electron's (cloud's) shape? So... it is "overall" spherical? It was always spherical?

Copernicus
2017-Oct-10, 02:29 PM
Hypothetically, let's say I didn't. You show me your hypotheses and I'll show you mine. Components? You mean the virtual-particles and their cloud?



The electron's directions? The directions were changing directions? And when the electron's directions change direction then that changes the electron's (cloud's) shape? So... it is "overall" spherical? It was always spherical?

No ablo elvish? Are you offering me food or insult?

Shaula
2017-Oct-10, 03:44 PM
The following article states the electron is round as far as we can tell due to the electric dipole moment. I am wondering if the same answer could be obtained from other perfectly symmetrical shapes?
https://phys.org/news/2017-10-jila-method-electron.html
Well for one thing they are not actually measuring any kind of physical 'roundness' of the electron. They are measuring the electron electric dipole moment. This is related to the distribution of charge with a non-zero value implying a deviation from perfectly spherically symmetric, and it is another assumption that the distribution of charge is related to a physical shape of the electron (on top of the assumption that it is meaningful to talk about an electron having shape). The electron could be shaped like a banana, this test would not identify that if the charge distribution were spherical.

DaveC426913
2017-Oct-10, 08:36 PM
Unless I am not up-date on the latest particle physics - electrons are considered to be point particles. They have no dimension.
It is only sensical to talk about their electric dipole moment, not about any supposed physical size or shape.

ShinAce
2017-Oct-10, 10:03 PM
An electric dipole moment for the electron would be incredibly small. Despite being a point charge, there are effects(CP violation) in the standard model that make it theoretically non-zero.

Measuring both the electron's and neutron's EDM is part of the search for physics beyond the standard model.

Copernicus
2017-Oct-11, 01:27 AM
Well for one thing they are not actually measuring any kind of physical 'roundness' of the electron. They are measuring the electron electric dipole moment. This is related to the distribution of charge with a non-zero value implying a deviation from perfectly spherically symmetric, and it is another assumption that the distribution of charge is related to a physical shape of the electron (on top of the assumption that it is meaningful to talk about an electron having shape). The electron could be shaped like a banana, this test would not identify that if the charge distribution were spherical.

That was my first thought.

joema
2017-Oct-11, 10:22 AM
....they are not actually measuring any kind of physical 'roundness' of the electron. They are measuring the electron electric dipole moment. This is related to the distribution of charge with a non-zero value implying a deviation from perfectly spherically symmetric, and it is another assumption that the distribution of charge is related to a physical shape of the electron (on top of the assumption that it is meaningful to talk about an electron having shape)...

Yes that's correct. Electrons are point-like particles with no physical size and no physical structure, whether round or any other shape. This is why the above article used "roundness" in quotes. Unfortunately the title did not use quotes which could imply to some readers the bare electron has a physical size and shape. It does not.

https://www.fnal.gov/pub/today/archive/archive_2013/today13-02-15_NutshellReadMore.html

Jens
2017-Oct-11, 12:42 PM
Maybe this should be a thread of its own, but if an electron is really a point, as an electron and positron approach one another, wonít the EM force (as well as gravitational force) go toward infinity? I guess thatís only in a classical world.

Shaula
2017-Oct-11, 01:18 PM
Maybe this should be a thread of its own, but if an electron is really a point, as an electron and positron approach one another, won’t the EM force (as well as gravitational force) go toward infinity? I guess that’s only in a classical world.
Every point charge is surrounded by a fuzzy cloud of self-interactions. This cloud means that the mass and charge of a particle doesn't appear the same at all scales. Neither does the interaction cross-section of this cloud. As you go to smaller scales (higher energies) the divergences caused by having point particles (ultraviolet divergences (https://en.wikipedia.org/wiki/Ultraviolet_divergence)) rapidly become unphysical unless you correct for this effect via renormalisation (https://en.wikipedia.org/wiki/Renormalization). There is a section on this (https://en.wikipedia.org/wiki/Quantum_field_theory#The_problem_of_infinities) in the history of QED article on Wikipedia.