2 ms·

Magnetic effects are local, since photons are sent between the objects; ie. distant objects don't interact with each other, they interact with photons locally,

Magnetic effects are local, since photons are sent between the objects; ie. distant objects don't interact with each other, they interact with photons locally, which then "carry" the force to the other object, where they again act locally. In fact, magnetism is a realtivistic effect; it's how the electrostatic force behaves when things are moving. "Spooky action at a distance" is something that's non-local, ie. there's nothing being transmitted between the objects; they "just know". Even if there were something being transmitted, it would have to be going faster than the speed of light. A great example is gravity; in Newton's model, gravity is spooky action at a distance, because objects (eg. planets) are in a pure vacuum, yet everything is aware of the location of everything else. General relativity replaces this with local interactions: objects are interacting with the spacetime around them, curving it; movement follows these curves; and changes propagate outwards at the speed of light, as (gravitational) waves.

danbruc 11y ago
Magnetic effects are local, since photons are sent between the objects; ie. distant objects don't interact with each other, they interact with photons locally, which then "carry" the force to the other object, where they again act locally. IANAP, but that is probably not a correct picture. Photons carry energy and therefore if you imagine electrically or magnetically charged objects sending out a constant stream of photons in order to mediate electric or magnetic forces you quickly get a problem with conservation of energy. In fact, magnetism is a realtivistic effect; it's how the electrostatic force behaves when things are moving. This also seems at least not accurate to me - relativity turns electric forces into magnetic forces and vice versa when you change reference frames, but they are not the same thing, they are two different aspects.
dools 11y ago
I'm not saying magnetism and entanglement are related, I'm saying that when we talk about forces between things, when we get down to it we have no more an understanding of how force "works" than we do how entanglement "works". We want everything to be like little machines with cogs and wheels and pulleys. But what is force? What is the thing that repels two negative charges? There's no "mechanism", that's just what force is and what it does. We're so comfortable accepting all this other shit about how the universe operates why should entanglement be any different?
- chriswarbo 11y ago
  Science is more than just accepting what we (experimentally) observe, since that would lead to a collection of facts rather than a theory. By looking for mechanisms, underlying causes, etc. we can find simple rules to explain seemingly unconnected phenomena. No scientist expects those rules to be intuitive; that's the realm of pop-sci "quantum woo" journalism. However, we do expect those rules to be consistent. General relativity and quantum mechanics are notoriously incompatible, so all of our attempts to combine them so far have been inconsistent, either internally (ie. the maths doesn't work) or externally (ie. they're toy models which can't explain real experiments). Bell showed that entanglement cannot be explained by local hidden variables, which was thought to be inconsistent with special relativity, since it seemingly allowed particles to communicate faster than light. More recently, work on quantum computation and quantum teleportation have clarified our ideas in terms of information: the speed of light is only a limit for information, and entanglement doesn't transfer information. Explanations like many-worlds are also based around information.
  - dools 11y ago
    The theory is the maths. Maths makes predictions, observation confirms those predictions. End of story. Local hidden variables are not required any more than a medium is required for an electro magnetic wave to propagate. And yes, it's correct that entanglement transfers no information! So there's nothing spooky about it; or more correctly it might seem spooky but there's no action at a distance.

danbruc 11y ago

Magnetic effects are local, since photons are sent between the objects; ie. distant objects don't interact with each other, they interact with photons locally, which then "carry" the force to the other object, where they again act locally. IANAP, but that is probably not a correct picture. Photons carry energy and therefore if you imagine electrically or magnetically charged objects sending out a constant stream of photons in order to mediate electric or magnetic forces you quickly get a problem with conservation of energy. In fact, magnetism is a realtivistic effect; it's how the electrostatic force behaves when things are moving. This also seems at least not accurate to me - relativity turns electric forces into magnetic forces and vice versa when you change reference frames, but they are not the same thing, they are two different aspects.

dools 11y ago

I'm not saying magnetism and entanglement are related, I'm saying that when we talk about forces between things, when we get down to it we have no more an understanding of how force "works" than we do how entanglement "works". We want everything to be like little machines with cogs and wheels and pulleys. But what is force? What is the thing that repels two negative charges? There's no "mechanism", that's just what force is and what it does. We're so comfortable accepting all this other shit about how the universe operates why should entanglement be any different?

chriswarbo 11y ago
Science is more than just accepting what we (experimentally) observe, since that would lead to a collection of facts rather than a theory. By looking for mechanisms, underlying causes, etc. we can find simple rules to explain seemingly unconnected phenomena. No scientist expects those rules to be intuitive; that's the realm of pop-sci "quantum woo" journalism. However, we do expect those rules to be consistent. General relativity and quantum mechanics are notoriously incompatible, so all of our attempts to combine them so far have been inconsistent, either internally (ie. the maths doesn't work) or externally (ie. they're toy models which can't explain real experiments). Bell showed that entanglement cannot be explained by local hidden variables, which was thought to be inconsistent with special relativity, since it seemingly allowed particles to communicate faster than light. More recently, work on quantum computation and quantum teleportation have clarified our ideas in terms of information: the speed of light is only a limit for information, and entanglement doesn't transfer information. Explanations like many-worlds are also based around information.
- dools 11y ago
  The theory is the maths. Maths makes predictions, observation confirms those predictions. End of story. Local hidden variables are not required any more than a medium is required for an electro magnetic wave to propagate. And yes, it's correct that entanglement transfers no information! So there's nothing spooky about it; or more correctly it might seem spooky but there's no action at a distance.