The speed of forces, and applying relativity to force carriers

In summary: The second is by someone who has done a lot of reading on the subject, but still has some misconceptions. "According to the quantum mechanics theory, all particles from elementary particles to big moleculesperform wave-particle duality property"This is not true, and is a common misconception. The first is by a "retired scientist", who knows little about the subject.This person has retired from a scientific field, and presumably knows a lot more about it than you do. If you read a modern paper on QM, it will be almost certainly incomprehensible to anyone who is not actively studying that subject.This is a common misconception,
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jaketodd
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Are there any limits to how fast forces can exert influence... or are they all instantaneous?

How fast are the forces of a collision?

I think frame dragging, with gravity, shows that at least gravity is not instantaneous, because if it is instantaneous, then how would it produce drag - it would affect everything around the gravitating body in no time? Unless it's not instantaneous, and maybe gravitons and/or spacetime warping have momentum and are on a non-straight trajectory from a rotating, gravitating body. That's interesting: Spacetime exhibiting momentum!

I've heard entanglement is either faster than light, or instantaneous.

In quantum mechanics, there are force carrier particles. So, since they travel so fast, is there time dilation or length contraction for those force carriers? Like for gravitons. As they travel through space to influence a body, is there time dilation or length contraction for the force carrier particles? How would we find out? If we can, then that would be a good step in uniting the two schools of thought!

Thanks,

Jake
 
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jaketodd said:
Are there any limits to how fast forces can exert influence... or are they all instantaneous?
No interaction in a relativistic theory (which includes quantum field theory) is instantaneous; the speed of light is a limiting speed for everything.

jaketodd said:
How fast are the forces of a collision?
When two objects collide, the forces involved are electromagnetic forces between the atoms in the objects.

jaketodd said:
I think frame dragging, with gravity, shows that at least gravity is not instantaneous
No, frame dragging by itself cannot be used to show anything about the speed of gravity.

jaketodd said:
because if it is instantaneous, then how would it produce drag
Frame dragging is not "drag" in the sense you mean.

jaketodd said:
maybe gravitons and/or spacetime warping have momentum and are on a non-straight trajectory from a rotating, gravitating body. That's interesting: Spacetime exhibiting momentum!
This is all personal speculation and is off limits here.

jaketodd said:
I've heard
Where? Please give a reference.

jaketodd said:
entanglement is either faster than light, or instantaneous.
You might find statements along these lines in pop science discussions of QM. They're not correct.

jaketodd said:
In quantum mechanics, there are force carrier particles.
More precisely, there are force carrier quantum fields, which, like all quantum fields, have certain states that are reasonably described as "particles".

jaketodd said:
since they travel so fast, is there time dilation or length contraction for those force carriers?
Neither of those concepts are useful for force carriers, no. Or for quantum fields in general.
 
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jaketodd said:
If we can, then that would be a good step in uniting the two schools of thought!
Special relativity and quantum mechanics are already fully united.
 
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jaketodd said:
Are there any limits to how fast forces can exert influence... or are they all instantaneous?

How fast are the forces of a collision?

I think frame dragging, with gravity, shows that at least gravity is not instantaneous, because if it is instantaneous, then how would it produce drag - it would affect everything around the gravitating body in no time? Unless it's not instantaneous, and maybe gravitons and/or spacetime warping have momentum and are on a non-straight trajectory from a rotating, gravitating body. That's interesting: Spacetime exhibiting momentum!

I've heard entanglement is either faster than light, or instantaneous.

In quantum mechanics, there are force carrier particles. So, since they travel so fast, is there time dilation or length contraction for those force carriers? Like for gravitons. As they travel through space to influence a body, is there time dilation or length contraction for the force carrier particles? How would we find out? If we can, then that would be a good step in uniting the two schools of thought!

Thanks,

Jake
You can certainly pack a large number of misconceptions into a single post. I seriously doubt you're learning any actual physics by throwing around vague misconceptions about GR, QM and particle physics all in one post.

You need to sort out each of these misconceptions and focus on one thing at a time.
 
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PeterDonis said:
No interaction in a relativistic theory (which includes quantum field theory) is instantaneous; the speed of light is a limiting speed for everything.

You might find statements along these lines in pop science discussions of QM. They're not correct.
There are some good ones here, which seem pretty reputable: https://scholar.google.com/scholar?q=light+quantum+entanglement+speed
 
  • #7
jaketodd said:
There are some good ones here, which seem pretty reputable: https://scholar.google.com/scholar?q=light+quantum+entanglement+speed
The first is by a "retired scientist", who knows little about the subject. If you read a modern paper on QM, it will be almost certainly incomprehensible to anyone who is not actively studying that subject. Papers that makes elementary statements such as the following are just not credible:

"According to the quantum mechanics theory, all particles from elementary particles to big molecules
perform wave-particle duality property"

That's garbage from someone who is regurgitating something they read in a popular science book, no doubt, and now is being regurgitated by you. PF is here partly as an antidote to this sort of nonsense that has flooded the Internet.

The problem is that for every valuable statement about modern science that you read, you probably read about 10-20 that are either wrong or misleading. This being a case in point.

You need to settle on a textbook; or, at worst a reliable popular science book that does not take too many liberties. Reading papers by crackpots gets you nowhere.
 
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jaketodd said:
There are some good ones here, which seem pretty reputable
Lots of "reputable" scientists say things in pop science articles, books, and videos that they know they would never get away with in a textbook or peer-reviewed paper. PF has rules about acceptable sources for a reason.

Thread closed.
 
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