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New Quantum Theory Topples Einstein's Spacetime

Third Eye Open

Graduate Poster
Third Eye Open
Joined
Mar 13, 2008
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Article:

Hořava’s theory has been generating excitement since he proposed it in January, and physicists met to discuss it at a meeting in November at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario. In particular, physicists have been checking if the model correctly describes the universe we see today. General relativity scored a knockout blow when Einstein predicted the motion of Mercury with greater accuracy than Newton’s theory of gravity could.
Can Hořřava gravity claim the same success? The first tentative answers coming in say “yes.” Francisco Lobo, now at the University of Lisbon, and his colleagues have found a good match with the movement of planets.
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What do you guys think, all hype? Or could there be something to this?
 
Good. Now I don't have to think about taking that Modern Physics class. It wasn't going to be for credit anyways.
 
I think it's great he has a Ř in his name. A sound 99,5% of the world's population will never be able to pronounce correctly. I hope he's right just for this fact alone :D
 
We will have to wait as many of us can not comment, however it is not an overturning of Einstein any more than Eistein overturned Newton.

It is an extension to current theory an area where current theory does not extend, the big issue would be if it can lead to GUT.

Warning I am a layman , all my comments are likely to be in error.
 
Oops, didn't click to the second page :o

Most physicists examined ideal cases, assuming, for instance, that Earth and the sun are spheres, Blas explains: “We checked the more realistic case, where the sun is almost a sphere, but not quite.” General relativity pretty much gives the same answer in both the scenarios. But in Hořava gravity, the realistic case gives a wildly different result.
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That doesn't sound good.
 
Ah, but shortly thereafter:

...Blas has reformulated Hořava gravity to bring it back into line with general relativity. Sibiryakov presented the group’s model in September at a meeting in Talloires, France.

Hořava welcomes the modifications. “When I proposed this, I didn’t claim I had the final theory,” he says. “I want other people to examine it and improve it.”
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tuc0 said:
I think it's great he has a Ř in his name. A sound 99,5% of the world's population will never be able to pronounce correctly.
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Well, it just wouldn't BE a real physics theory (or math concept) if it didn't have an utterly bizarre name to attach to it.
 
Third Eye Open said:
Article:



What do you guys think, all hype? Or could there be something to this?
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It's hype, unfortunately. It looked interesting when it first came out, but it quickly became apparent that it is more in the class of "vague idea" than it is "theory". There are many mathematical miracles required for it to work, none of which have been demonstrated - in fact there aren't even examples of simpler theories in which similar miracles work.

(If you're curious, the biggest technical problem is the claim that the theory flows to general relativity - or even anything Lorentz invariant - at low energies. There is zero evidence that should happen, and there are no known examples, to my knowledge, of interacting theories with a non-Lorentz invariant UV fixed point that flow to something Lorentz invariant in the IR. There aren't even simple field theory examples, let alone something as complex as this. Then there's the fact that there are multiple free functions worth of parameters. It doesn't look promising.)
 
Y'know, I haven't read this and I am much less qualified to comment than Sol is.

However: when someone says "I have a theory that reduces to GR at low energies"---or even "I have a theory that I hope can be made to reduce to GR at low energies"---then I would not begin to say that something "topples Einstein". I mean, that's what everyone wants a theory-of-everything to do: to look like GR in one limit and to look like QFT in another limit and to look like something sensible when both limits seem to apply, like near a singularity or early in the Big Bang.

So these are all good directions to be thinking in---unlike the standard *crackpot* version of "toppling Einstein* in which you decide to derive the Fine Structure Constant from the mass of Jupiter and show that GR never worked to begin with. Does Horava have it right with this particular attempt? I dunno, and it sounds like Horava doesn't know either---if Sol is right then perhaps his chances are low. But it sounds like the ingredients of non-crackpot science are there, and therefore smart people will work on it and we'll learn the answer eventually.

(It also sounds like: "Whoa, sounds like something out of the Perimeter Institute." And so it is!)
 
ben m said:
However: when someone says "I have a theory that reduces to GR at low energies"---or even "I have a theory that I hope can be made to reduce to GR at low energies"---then I would not begin to say that something "topples Einstein".
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Yes, it's crappy science journalism (all too typical, unfortunately).

So these are all good directions to be thinking in---unlike the standard *crackpot* version of "toppling Einstein* in which you decide to derive the Fine Structure Constant from the mass of Jupiter and show that GR never worked to begin with. Does Horava have it right with this particular attempt? I dunno, and it sounds like Horava doesn't know either---if Sol is right then perhaps his chances are low. But it sounds like the ingredients of non-crackpot science are there, and therefore smart people will work on it and we'll learn the answer eventually.
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Yes, absolutely. It's certainly not crackpot, just highly speculative and ambitious.
 
Okay, I know how the R in Dvorak is pronounced...

So Horava is pronounced Horzhava?
 
You have to use your BS detector on science news just as much as the paranormal. The important question is, "What does this new theory really tell us about the Universe, and what sort of experiment could be performed to prove it?"

The two big unanswered questions are (1) What is the nature of Gravitation? Does it have a cause, a mechanism by which it propogates? (2) How do we explain Gravitation in a way that does not conflict with Quantum Mechanics?

The articles about this new theory hint that they may provide answers, but I don't see any information on what the answers themselves might be. Until I see how this theory explains Gravitation in a way that is novel and unique, and an advancement over General Relativity, there is no news here.
 
There are surprisingly a lot of articles written every now and then on how "new" discoveries or theories prove Einstein wrong. Not long ago this was done through effects like entanglement.

It appears to offers 'hints' of the potential in quantum entanglement to violate Special Relativity. I don't see that it does though, because even if a particle can appear to communicate in a given way, instantenously, with an undisturbed 'partner-particle', it can't really send actual data this instant way, and if there can be no data transmitted this way then it does not violate SR.
 
Richard S said:
You have to use your BS detector on science news just as much as the paranormal.
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This is even true of the Science magazine general reporting. I subscribe to the journal, and the actual science in it is always astonishing and groundbreaking. The reporting on the articles, however, are often lacking. It is frequent that when I read an article on a geological phenomena and the accompanying "general audience" write up, the two do not correspond, and the significance of studies is often stated incorrectly (not always overstated, but often applied beyond what the study really suggests). This is especially true of the "sciencemag.org" site, which is intended for a general audience. It aggregates stories that they think will be interesting to a general public, and the results are sometimes that they have a story with little content, or a story that inaccurately reports the findings. It almost always strips the hard evidence down to a sentence or two, if that, and usually gets things wrong.

Of course, reporting in general always needs to be taken with a big grain of salt. The paper ran an article on me a few months ago when I rode my unicycle to New Orleans, and they managed to get factual information incorrect on a story even that simple.
 
I was at a talk on this today. I didn't understand much. What I did get, and paraphrasing a lot is that
a) noone really thinks this is a complete theory of gravity
b) at least one variant of it is ruled out, if not all of them
c) it's still interesting

I get the impression that considering is the sort of thing that moves research forward - it obviously isn't easy to pull a fully functioning quantum theory of gravity out of thin air and ideas like this help people consider what approaches are good ones.
 
edd said:
I was at a talk on this today. I didn't understand much. What I did get, and paraphrasing a lot is that
a) noone really thinks this is a complete theory of gravity
b) at least one variant of it is ruled out, if not all of them
c) it's still interesting

I get the impression that considering is the sort of thing that moves research forward - it obviously isn't easy to pull a fully functioning quantum theory of gravity out of thin air and ideas like this help people consider what approaches are good ones.
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Yes science is a lot about going through trial and errors. If a theory or idea valid for one gets kicked, punched, scaulded enough and still left standing, you know there's probably something there.
 
WhiteLion said:
Yes science is a lot about going through trial and errors. If a theory or idea valid for one gets kicked, punched, scaulded enough and still left standing, you know there's probably something there.
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So, science is like Rocky? :D
 
Just as vapourware is only vapourware until it is delivered, so too is an hypothesis only an hypothesis until it is demonstrated in a practical way.

Hype.
 
I'm not really seeing a hypothesis here. Just an observation that we have a new model that is not based on "spacetime" but rather on a de-coupling of space and time, and the resulting math seems to fit certain observations better. But on a deeper level there is no "truth" being revealed here.

Both classical Newtonian mechanics and Einstein's GR are valid scientific theories because they meet the criteria of being testable and falsifiable. The big win is if your theory makes predictions that you can go out and test and get positive results that the earlier theories didn't predict, or predicted incorrectly. This is why GR sits on top of Classical Mechanics, but both are still treasured as the "crown jewels" of science.

I'd say it's a matter of debate whether GR really "falsified" Newton's mechanics. It would be more accurate to say that Newton got everything right, and it's only the most modern measuring devices, push to the absolute limits of their ability, that can find cases were GR gives a result that is more accurate than what Newton would have predicted.

Show me how Horyava's theory meets those criteria, and you will have my attention.
 
My point is that its value may not be in being a good description of gravity but as a toy model demonstrating approaches that may get us there. Describing it as vapourware and hype is not that helpful.
 
edd said:
My point is that its value may not be in being a good description of gravity but as a toy model demonstrating approaches that may get us there. Describing it as vapourware and hype is not that helpful.
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Not helpful, but accurate!

Nothing has been proven or demonstrated; thus hypothesis and vapourware, respectively.
 
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Vapourware is something that doesn't exist. This theory exists, it just happens not to be correct - and being incorrect does not render it without value. It's nothing like vapourware - it's an entirely inaccurate description.
 
Richard S said:
I'd say it's a matter of debate whether GR really "falsified" Newton's mechanics.
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Relativity certainly didn't falsify Newtonian mechanics. It was failing to make predictions that matched observed phenomenon that did that. In fact, that's the only way you can ever falsify a theory, simply proposing another theory can never do that.

It would be more accurate to say that Newton got everything right, and it's only the most modern measuring devices, push to the absolute limits of their ability, that can find cases were GR gives a result that is more accurate than what Newton would have predicted.
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No, that wouldn't be accurate at all, since Newton demonstrably didn't get everything right. That was known well before Einstein ever came along and didn't require any modern devices or pushing anything to its limits. What is actually correct to say is that Newtonian mechanics gives answers that are close enough to reality to be good enough in most situations. Relativity gets everything a lot closer to reality, but still seems to have a few problems here and there.
 
Richard S said:
I'd say it's a matter of debate whether GR really "falsified" Newton's mechanics. It would be more accurate to say that Newton got everything right, and it's only the most modern measuring devices, push to the absolute limits of their ability, that can find cases were GR gives a result that is more accurate than what Newton would have predicted.
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It's not that Newton's work was proven wrong, per se, by Einstein but rather that it was proven incomplete, limited as it were.
You see, as past significant breakthrough's in, for example, theoretical physics were in their own way correct, they were oft limited as to not account for other layers of dynamics. Relativity is solid at a macroscopic level yet at the levels of QM there suddenly appears a variety of issues and problems. This is why, in science, we specify a theory's solid/valid status through its specific 'domain of application', because we do not have a UFT yet (Unified Field Theory) really encompassing all laws.
 
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