# "(Alpha)" Unified Field Theory?

Discussion in 'Physics & Math' started by Uno Hoo, May 28, 2008.

1. ### Uno HooRegistered Senior Member

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For many long decades scientists have sought a Unified Field Theory. ( The two that really count; electricity and gravity.). Maxwell gave it a good shot. So did Heaviside. And many others. Einstein struck out swinging four times. More or less.

So, are we ever going to have a Unified Field Theory? Or, are electricity and gravity just simply two forces so alien that never the twain shall meet?

3. ### BenTheManDr. of Physics, Prof. of LoveValued Senior Member

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We should be clear what you mean by unified field theory''. You seem to be talking about a Theory of Everything---that is, unification of the three forces with gravtity.

Is this correct?

5. ### Uno HooRegistered Senior Member

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"The two that really count; electricity and gravity".

When my initial post referenced electric force and gravity, that was, I thought, a reliable clue that I was actually talking about electric force and gravity.

Another good clue was that I referred to Maxwell, Heaviside, Others, and Einstein. ( None of them had ever clairvoyantly looked into their future to know anything about a theory of everything.) But they all wrote theories attempting to unite electric force with gravity force. I am sure you already knew that and are just playing a good natured joke on me.

My curiosity would be satisfied if I only knew of a workable theory that related the manipulation of electric force to the manipulation of gravity force ( or, of course, vice versa). And if I can read the opinions of such learned folk as you (all).

By The Way; gravtity is correctly spelled g r a v i t y ( with only one t).

7. ### AlphaNumericFully ionizedModerator

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Kaluza Klein compactification of 5 dimensional general relativity. Except it's not quantised.
By the way, Ben knows a trillion times more about GUTs, gravity including or not than you. Can you spell 'typo'?

8. ### FarsightValued Senior Member

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No. We're never going to have a Unified Field Theory, because when you unify the fields, you lose them. You end up with a Unified Theory.

See the American Institute of Physics website http://www.aip.org/history/einstein/index.html which gives an excellent Einstein history. You can view parts of papers such as A New Form of the General Relativistic Field Equations written in 1955 with assistant Bruria Kaufman.

Also see Unified Field Theories and Einstein by S C Tiwari at http://arxiv.org/ftp/physics/papers/0602/0602112.pdf and note the quote "Einstein, in his last paper on the subject, admitted that perhaps the concept of field was inadequate for the unified theory which he was seeking".

9. ### QuarkHeadRemedial Math StudentValued Senior Member

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You know for sure, right? You can prove it? This seems so unlikely as to be laughable, your ability to prove it, that is.

10. ### BenTheManDr. of Physics, Prof. of LoveValued Senior Member

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Unifying electromagnetism and gravity is a pretty useless enterprise, mainly because there are two other forces to include.

11. ### ReikuBannedBanned

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Yes, not only does he know for sure, so do i.

Hawking has made the obvious point, that even if we do manage to create a GUT, there is no way to determine the likelihood of the greater number of chaotic systems. This means, that when we think we have the equation right, there is the shadow that a spontaneous reaction would change everything.

This must render the notion of such a concept uneasy.

12. ### QuarkHeadRemedial Math StudentValued Senior Member

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Then may I trouble you for your proof that no unified field theory will ever be found? Or, if not a proof, the reasoning behind this rather extravagant claim?

13. ### ReikuBannedBanned

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Unless all of sudent, you have a machine that can predict the lottery, then there is enough reasoning.

14. ### BenTheManDr. of Physics, Prof. of LoveValued Senior Member

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This is not what theory of everything'' means, surely you know that.

15. ### ReikuBannedBanned

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I'll just take it you never followed where i was going with that... hold on...

16. ### ReikuBannedBanned

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I was informing our friend, that a unified theory could never be totally sure to be correct, because at any point in the future, or some unbeknown event in the past, can suddenly alter and drastically change a theory.

Our friend wanted to know where the proof of such a claim is, [especially] when we may have found the theory... i was simply pointing out that line of thought was erreneous. Instead, if we do accomplish a theory of everything, then there is no way we can know its future or past state UNLESS...

... He had a time machine that can say otherwise. This is why any attmept at a unified theory would be incomplete.

17. ### BenTheManDr. of Physics, Prof. of LoveValued Senior Member

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The idea behind a theory of everything'' is not to predict the outcome of every single event---quantum mechanics even tells us that this is not possible. Theory of Everything'' means a unified theory of gravity and the three other fundamental forces.

18. ### ReikuBannedBanned

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OH i know... i mearly pointing out that the unfication, of electro-magnestism and gravito-strong and weak forces need to finally predict the outcome of a universe, and even an entire universe can be subject to Chaos Theory... this is why it is impossible to be definate, even with a unified theory.

19. ### ReikuBannedBanned

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When i said, ''A time machine that predicts the future,'' it may have been a bad example. But in the end, the analogy was to show the uncertainty inherent in the future.

20. ### ReikuBannedBanned

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Besides... don't GEM equations combine gravito-electromagnetic forces together>

21. ### Uno HooRegistered Senior Member

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Every statement in my reply was correct. You have the burden of proof to prove otherwise.

It is easy for you to to say " Unifying electromagnetism and gravity is a pretty useless enterprise", but is not so easy to prove any credence of such a statement. You are free to prove your statement if you think you can. My guess is that a large number of people would find immense usefulness in being able to manipulate electricity to accomplish the manipulation of gravity, or, to somehow manipulate gravity and get the result of manipulating electricity.

It is puzzling to an extreme to read you saying " mainly because there are two other forces to include". In my universe the two nuclear forces have been unified with electricity for some time now. I think it may have been in quantum physics. Do you have quantum physics in your parallel universe?

In my universe one of the main obstacles to the unification of electricity and gravity is the fact that electricity is based on a theory of field equations which are perfectly straightforward regardless of the speed of the electric bodies, whereas gravity is presently based on a theory of field equations which do conniptions regarding the speed of the gravitating bodies.

Your response to my post(s) subtly hint that you are not willing or able to confront the issues of considering the unification of electricity and gravity. Electricity, in the form of quantum physics, is superlatively well established theoretically. It is reasonable that unification will require scrapping of current gravity theory and invention of a new gravity theory based on compatible field equations.

Perhaps you somehow are bashful about openly admitting that current gravity theory will have to be trashed.

Have I guessed right?

22. ### AlphaNumericFully ionizedModerator

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No, you don't. Or else we'd not have fields in our unified electrweak model.
Einstein did very little right after about 1930. Not helped by the fact he didn't even know about the weak and strong forces. And his idea hasn't played out despite more than 50 years since he died.
This is precisely the claim you made and I corrected which prompted your "I know more than you" physics challenge on PhysOrg.

You're wrong.

A GUT would be writing down the equations of motion (or more specifically, the Lagrangian) for a quantised setup for the 4 fields. That's all. We can write down the equations of motion for plenty of chaotic systems. Besides, 'chaotic' implies deterministic, which quantum mechanics isn't.

The existence of chaotic systems has nothing to do with finding a GUT. Obviously you learnt nothing from that thread.
So despite claiming to know about GUTs on PhysOrg and despite being corrected on pretty much everything you said, you still haven't even looked up what a GUT is.

And you wonder why Ben and I have to keep correcting you.
And that's irrelevent.

We cannot even solve the equations of motion for an electromagnetic system but we have a full quantum theory for it, unifying electric and magnetic concepts. We cannot solve the equations of motion for an electroweak system but we have a full quantum theory for it, unifying weak and EM concepts.
Classically.
That isn't a unified model, that's a dual model.

As I said, Kaluza Klein compactification leads to a theory with gravity and classical electromagnetism in it but it's not phenomenologically useful. To have a model which allows manipulation of gravity and under some transformation gives you electromagnetism would be useful, except it'll be more complicated than just doing electromagnetism directly. Similarly for gravity. Classically they are pretty straight forward for most practical things.

There is a dual mapping between the strong force and gravity which is very useful precisely because the strong force is very much more complicated, due to things like strong coupling and confinement. It's known as the AdS/CFT correspondence in string theory and is a huge area of research.
No, you haven't guessed right. GR is experimentally verified to a huge degree. This means that any new theory must reduce to GR at lowish energies, just as GR must (and does) reduce to Newtonian gravity at very low energies. All dual models and models which already combine gravity and electromagnetism lead to the same result, that GR is a valid classical limit of gravity. It's only at tiny distances (and so high energies) that the difference is apparent.

23. ### EntropyAlwaysWinsTANSTAAFL.Registered Senior Member

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I cringe every time I hear someone say this or anything similar.

Rules of a logical argument:
1. Statement / proof.
2. Rebuttal / disproof.
3. Response and further evidence.
go to 2.

What many people fail to understand is that when you disagree with an established scientific principal, one that has been rigorously tested, is that you are playing the role of step 2 and hence must FIRST disprove the argument in question, not simply state your disagreement, BEFORE the burden of proof is passed from you.