I Is there action at a distance at the atomic level in physics?

[sahashmi]

TL;DR Summary

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When atoms interact each other, are they interacting through some form of force that propagates between the atoms, or is this action occurring at a distance?

Newton’s gravity theory famously posited action at a distance: objects affecting each other at a distance with nothing propagating between them in space. Now, we know that gravitational waves propagate between masses.

I’m now curious as to whether interactions in the atomic realm are “at a distance” or always through forces propagating through space

 

[Nugatory]

TL;DR Summary: See title

When atoms interact each other, are they interacting through some form of force that propagates between the atoms, or is this action occurring at a distance?

Newton’s gravity theory famously posited action at a distance: objects affecting each other at a distance with nothing propagating between them in space. Now, we know that gravitational waves propagate between masses.

I’m now curious as to whether interactions in the atomic realm are “at a distance” or always through forces propagating through space

You can treat the problem classically, in which case the forces between atoms are electromagnetic, so carried by the electromagnetic field, no action at a distance. Of course this treatment will only work in a few cases; more often we get results that don't match observation, such as the classical prediction that atoms are unstable.
Or you can treat the problem quantum mechanically, in which case the question is meaningless - there's no notion of forces propagating between particles located at points in space. We get results that match our measurement result and that's as good as it gets with QM.

Newton’s gravity theory famously posited action at a distance: objects affecting each other at a distance with nothing propagating between them in space. Now, we know that gravitational waves propagate between masses.

Off topic here, but that second sentence is a non-sequitur, unrelated to the first.

 

[PeterDonis]

When atoms interact each other, are they interacting through some form of force that propagates between the atoms, or is this action occurring at a distance?

How would you do an experiment to tell the difference?

Newton’s gravity theory famously posited action at a distance: objects affecting each other at a distance with nothing propagating between them in space. Now, we know that gravitational waves propagate between masses.

"Gravitational waves propagate between masses" is not how, for example, the Earth and other planets remain within the Sun's gravitational field in GR. GR does predict gravitational waves, but it does not say that all "gravitational interactions" between masses are due to propagating gravitational waves.

 

[PeroK]

TL;DR Summary: See title

I’m now curious as to whether interactions in the atomic realm are “at a distance” or always through forces propagating through space

Neither. It was Heisenberg who first realised that interaction between elementary particles could only be described mathematically. These mathematical calculations are what modern particle physics is all about. The main tool in this respect is the so-called S-Matrix, derived from QED/QFT:

https://en.wikipedia.org/wiki/S-matrix

For example, electron-positron interactions are described as Bhabha scattering. This was first calculated by Bhabha in 1935. If you were a graduate particle-physics student this is what you would spend your time learning:

https://en.wikipedia.org/wiki/Bhabha_scattering

 

[martinbn]

This is just a refusal to accept quantum theory. You want a classical explanation, and because there cannot be a local classical one, you look for an "action at a distance" classical explanation.

 

[sahashmi]

This is just a refusal to accept quantum theory. You want a classical explanation, and because there cannot be a local classical one, you look for an "action at a distance" classical explanation.

No, I want an explanation, “classical” or not

 

[apostolosdt]

Nice, provocative question. As a starter, look into Wheeler-Feynman’s theory; perhaps the Wikipedia article on action at a distance. But keep it “low” and confine it to electromagnetism only.

 

[martinbn]

No, I want an explanation, “classical” or not

Well, quantum mechanics is an explanation! But you don't accept it. You want a different one, you want a classical one.

 

[PeterDonis]

I want an explanation, “classical” or not

What your posts show that you want is to keep harping on the same questions regardless of the answers you get. Enough is enough.

This thread is closed.