Correspondence Principle vs Emergence

Matterwave

The correspondence principle is not even a "law" in quantum mechanics. It is merely a guiding principle in its construction. For large quantum numbers, classical results "should" be reproduced. This is not ALWAYS the case. For example, super conductivity is a purely quantum mechanical effect which has no real analogue (AFAIK) in classical mechanics, but this is observed in macroscopic scales (someone correct me if I'm wrong here).

The only real principle is that we should not destroy the "working" parts of current theories with a new theory because we have made a lot of experimental tests of these "working" parts. For example, SR mechanics limits to Newtonian mechanics in the limit of low velocities. GR limits to Newton in the limit of low velocities, and low curvature.

The essence of the correspondence principle is merely that we should not have a theory that says, for example, that a 1kg object subject to a 1N force would be accelerated at 300m/s/s. We've taken a lot of these kinds of measurements, and they all suggest that Newton's laws works for these typical every day objects. We shouldn't have a theory that cannot at least explain these every day phenomena.

Varon

Can you give another example in physics where something in newtonian is really violated by SR and QM? Right now.. it's more like SR works at very fast speed and QM works at very small object.. so newtonian middleweight is not affected at all, isn't it. I don't know how to verbalize this or express it. I'm like asking why make newtonian like a reference. I'm looking for example in physics where something like newtonian is just temporarity and just emergence of a completely different theory. Can you give an example if you see what I'm thinking?

Matterwave

SR works at ALL speeds. It's only that for low speeds, Newtonian physics is a good approximation. But if you want to go to higher levels of accuracy (say, 8-10 decimal places or something like that), then even at normal speeds, you need SR.

Physics is not disjoint in that sense. It's not like SR is valid for speeds from 300km/s+ and Newtonian is good for lower. There's a smooth transition where Newtonian predictions get worse and worse as the speeds get higher and higher.

Varon

Ah. So it is about laws like f=ma being obeyed at all times. Of course. But if say the universe is multi branes.. then simply add more numbers to m or a or solve for multiple f like f in each brane.

So I guess teleportation is more to do with complete overhaul of QM and SR/GR. This means newtonian is only valid for laws like f=ma but it can be of any nature hidden inside it.

Drakkith

Newtonian isn't "affected" because it works just the way it should in the range of values that it should. Exceed those boundaries and it begins to become inaccurate. SR, GR, and QM all work pretty much just fine at everyday velocities and sizes, however because they can be much more complex than Newtonian laws, it is usually MUCH easier to use Newtonian rules where you can.

Drakkith

Think of it like this. If we found some bizarre region of anti-space or something, and applying a force to an object resulted in 10 times the normal acceleration of that object, nothing in current physics would be wrong really because no current theories deal with said anti-space.

Varon

Ok. Whenever I think of newtonian. I imagine a world made of solid stones and continuous things just like people in the time of Newton did. But for you physicists. Newtonian is about law like f=ma and not about imagining solid stones, isn't it.

I guess QM, SR, GR are just like another Newtonian where a higher theory with more complete degree of freedom can supercede it. But here's the problem. Some part of QM, SR have to be shattered. In the Quantum-Newtonian example. Did we shatter any newtonian part to become quantum?? Hmm.. does decoherence and classical to quantum transition counts as one?

I guess it's now time for another major breakthrough and paradigm shift in physics where there would be quantum/SR/GR to (Final Theory) transition just like quantum to classical transition in quantum decoherence. My analogy is accurate. isn't it?

StevieTNZ

See 'Sneaking a Look at God's Cards' (pages 348-350), and 'Interpreting the Quantum World' [by Jeffrey Bub] (pages 216-217) for more information on decoherence.

Varon

In the time of Newtonian, time being dilated and quantum superposition is against the law of newtonian.. but QM and SR supercedes it. In the time of Obama, objects being fully teleported is against the law of QM, SR and GR... but the Final theory supercedes it.

Does this analogy hold? My problem is that SR works precisely to hide any preferred frame. Full object teleportation can violate SR because it needs preferred frame or else causation is violated. Hence in this case SR must proven false for this kind of Teleportation to exist?? Right?

Matterwave

I wonder, why are you so hell-bent on this teleportation thing? Why do you think the "final" theory must allow teleportation?

Varon

To avoid this message getting deleted. Let's just say that it is due to elegance. Teleportation is elegance. When Einstein thought of spacetime curvature or time dilation, it was elegance.
Anyway. With nature having unlimited imaginations allowing the possibilities of quantum mechanics superposition or spacetime curvature for example.. It has at its disposal anything allowable and thinkable. Teleportation is one. It is natural. It's unthinkable if nature won't make use of it.

What we have in our standard model are just default mode. Enhance mode would produce all those degrees of freedom. So hope scientists can figure it out soon... I wonder what would happen if their model building allows for Teleportation. Who knows. Unexpected discoveries would even come up.

Drakkith

Your view is simply not a scientific one then.

Varon

Hope it got into one of CERN creative model building contests where contestants were ask how they could manipulate the present laws of physics to make possible the teleportation of objects that doesn't use the concept of wormholes.

Matterwave

Hmmm, but why teleportation specifically? There are a lot of other exotic phenomena that can exist in our imaginations. Anti-gravity machines, or time machines, or free energy machines, etc etc...why focus on teleportation? I don't really get it.

Varon

Because it stretches or shatter spacetime and overturn the quantum. It is a great way to think of quantum spacetime which is a more general case (quantum gravity being just a specific use of quantum spacetime).

Drakkith

I think I'm too tired to understand this. Off to bed for me!

Varon

In case large scale object teleportation were part of nature. Would we want it public knowledge? For the security of the world. It must be hidden to avoid Al Qaeda teleporting nukes in the heart of Washington for example. Therefore the following must be so:

Newtonian physics = physics of the masses and average man on the street
QM, SR, GR, Gauge Theory, Standard Model = physics of scientists
Final Theory (with Teleportation) = super physics of the Elite.

Therefore I agree that these Final Theory if ever it included Teleportation must be suppressed and kept hidden from public and world scientists. Instead let's give them decoys like String Theory to waste their time in wild goose chase. Lol