Quadruply Special Relativity is Impossible

[Martin]

Chryssomalakos and Okon just posted this paper

 

http://arxiv.org/hep-th/0407080

 

I think it has an important result

that completes a major paper by Kowalski-Glikman and Smolin

called Triply Special Relativity

 

K-G and S show that you can jack relativity up to where 3 quantities are constant (same for all observers)----speed of light of course, that was the original circa 1900 modification, bending the square newtonian framework so that c is the same for all observers----but then you can further bend the symmetries so that two more quantities are invariant: a mass and a curvature

 

Now C and O have shown that you cant jack it up any farther.

What Kowalski-Glikman and Lee Smolin did last month is the limit

Here's the link to K-G and S paper from June 2004.

http://arxiv.org/hep-th/0406276

[jana]

I noticed that you give good answers on the subject of astrophysics at the level of freshman physics courses. I think you do so because you understand this material well enough to answer in a way that the kinds of people who populate this site can understand. If this is true, then I think you must know that hardly anyone here has any chance of understanding any of the papers to which you are so fond of giving links. But there is nothing in this or any of your other posts at SFN to indicate you understand these papers yourself. So why should anyone here take seriously your opinion that the above paper on doubly special relativity (which btw is a highly speculative idea which few physicists, and certainly not the top ones, take seriously) is important?

 

I've very politely asked you more than once to backup your claims, and all I've ended up getting from you are insults. So I'll give you yet another chance. Why should we take the work on doubly special relativity seriously? For example, does it solve or provide a better approach to some outstanding problem?

[Martin]

http://www.scienceforums.net/forums/showthread.php?p=65900#post65900

 

here is an example of someone expressing a low opinion of people at this site----or declaring that they do not understand such and such, which the person assures us he does

 

it is possible that the delusions of superiority exhibited are just that, delusions

 

but that doesnt matter

 

the population at a science board is volatile. It doesnt help to knock the site and say there is no one here who can understand whatever. Maybe someone does, or maybe someone who does will drop in unexpectedly and comment!

 

Having you around saying "Nobody here understands Quantum Gravity!" does not make the place more inviting to newcomers and visitors. But maybe they will not pay any attention to you and join in regardless.

 

I think this paper by Chryssomalakos and Okon is fascinating and i would like to find someone here at SFN who wants to discuss it. I will say more about it, I guess, to make it clearer why it is so interesting.

 

there is a move afoot to extend special relativity

and observational astronomers are getting set to test the premises of any extension

 

it doesnt do any good to disparage those working on extensions--- like Lee Smolin, Jerzy Kowalski-Glikman, Etera Livine, Daniele Oriti, Florian Girelli, these people (Chrysso and Okon)---and say they are not "first rate scientists"

We will see. Something besides status is at stake. People are going to try to extend relativity so as to keep the Planck length invariant (as well as the speed of light) because several approaches to Quantum Gravity appear to call for this. And the observational people are going to test it.

[jana]

http://www.scienceforums.net/forums/showthread.php?p=65900#post65900

 

here is an example of someone expressing a low opinion of people at this site

 

I'm pretty sure that the site administrators can verify that jeffrey winkler is connecting from hartford conneticut as he claims and that I'm connecting from toronto ontario' date=' or at least that I'm connecting from canada and that winkler is connecting from the states. In fact, under the circumstances, I would appreciate very much if they would do so and let you know what they find. I emailed winkler to ask him what the deal was with him and you, but he hasn't responded.

 

People are going to try to extend relativity so as to keep the Planck length invariant (as well as the speed of light) because several approaches to Quantum Gravity appear to call for this. And the observational people are going to test it.

 

Interesting. I'm going to look into this right and try to get back to you as quickly as I can.

 

Edit: I forgot to ask what papers you suggest I look at.

[jana]

People are going to try to extend relativity so as to keep the Planck length invariant (as well as the speed of light) because several approaches to Quantum Gravity appear to call for this. And the observational people are going to test it.

 

 

I could be wrong (and probably am), but from Introduction to Doubly Special Relativity I’m getting that it’s not in fact a matter of certain approaches to quantum gravity requiring something like DSR. However the motivation of DSR by the "cosmic ray paradox" seems easy enough to understand. But from a paper entitled Doubly Special Relativity I’m getting that even the people directly involved in this research admit that it’s all quite speculative.

 

I'm going to ask john moffat what he thinks about this stuff since this kind of thing is right up his alley, as I guess you must already know.

[Martin]

Hello J,

I have inserted the authors of the articles you cited, to get an idea of what "introduction to DSR" you mean---I see a lot of articles and can get confused unless i see authors name, title of the article, and link.

 

I think what you are reading is fine, though personally i would not recommend the 2002 one by A-C.

 

I could be wrong (and probably am), but from Introduction to Doubly Special Relativity I’m getting that it’s not in fact a matter of certain approaches to quantum gravity requiring something like DSR.

 

Jerzy K-G

Introduction to DSR

http://xxx.lanl.gov/abs/hep-th/0405273

 

However the motivation of DSR by the "cosmic ray paradox" seems easy enough to understand. But from a paper entitled Doubly Special Relativity

 

Giovanni A-C

Doubly Special Relativity

http://xxx.lanl.gov/abs/gr-qc/0207049

 

I’m getting that even the people directly involved in this research admit that it’s all quite speculative.

 

I'm going to ask john moffat what he thinks about this stuff since this kind of thing is right up his alley, as I guess you must already know.

 

If I had a chance to talk with John Moffat I would ask him about his latest paper, and the recent paper by Girelli, Livine, and Oriti which cites it.

 

Here is the John Moffat article:

Modified Gravitational Theory as an Alternative to Dark Energy and Dark Matter

http://arxiv.org/astro-ph/0403266

 

Here is the Girelli Livine Oriti paper

Deformed Special Relativity as an effective flat limit of quantum gravity

http://arxiv.org/gr-qc/0406100

 

Here is another recent, closely related one by Lee Smolin and Jerzy K-G

Triply special relativity

http://arxiv.org/hep-th/0406276

 

Please dont misunderstand. I am not urging you read any of these three papers. but if I could talk with Moffat i would ask him if he sees any connection between Triply Special (either Smolin's or Girelli et al's) and what he is interested in. Girelli et al suggest a possible tie-in, but it seems very tenuous. i would like to know Moffat's take on it.

 

I believe I personally would not want to read anything written about this stuff before 2004----but I might change my mind. It has been written about for many years but what I see happening now looks like something new opening up. However I'm open to suggestion so if you find anything you think is particularly enlightening on it, written earlier, please let me know.

 

BTW If you really are posting from Toronto then I shall consider you to be the (not winkler!) whom i recall from other forums. the style and turn of thought is familiar but I now realize it is that of you and (not winkler!)

[JaKiri]

Bah, now I have to install acrobat again

[Martin]

Bah, now I have to install acrobat again

 

hooray for the arXiv!

hooray for preprints in PDF!

sorry about that

(it is really great to have immediate access to the latest

research papers, though)

[jana]

I see a lot of articles and can get confused unless i see authors name, title of the article, and link.

 

I'll be sure to provide this info in the future.

 

Here is the Girelli Livine Oriti paper

Deformed Special Relativity as an effective flat limit of quantum gravity

http://arxiv.org/gr-qc/0406100

 

This paper looks very interesting. I'm going to read it.

 

Please dont misunderstand. I am not urging you read any of these three papers

 

Don't sweat it.

 

BTW If you really are posting from Toronto then I shall consider you to be the (not winkler!) whom i recall from other forums. the style and turn of thought is familiar but I now realize it is that of you and (not winkler!)

 

I've made my email address available. Note the ".ca" part.

[blike]

Jana is in Toronto, and is not Winkler

[Martin]

Jana is in Toronto, and is not Winkler

 

thanks

 

whew!

[jana]

Jana is in Toronto, and is not Winkler

 

Thanks.

[Martin]

so who is teaching the undergrad string course

at Toronto this fall?

[jana]

so who is teaching the undergrad string course

at Toronto this fall?

 

They cancelled it. But I'm going to audit the graduate course which I believe will be taught by amanda peet.

[jana]

Okay, I'm ready to make one comment on the "Deformed Special Relativity as an effective flat limit of quantum gravity" paper.

 

It seems to me that for this whole scheme to have any chance of working the energy scale given by kappa must lie below the energy scale at which the first correction to the hilbert action of GR becomes important.

[Martin]

Okay' date=' I'm ready to make one comment on the "Deformed Special Relativity as an effective flat limit of quantum gravity" paper.

 

It seems to me that for this whole scheme to have any chance of working the energy scale given by kappa must lie below the energy scale at which the first correction to the hilbert action of GR becomes important.[/quote']

 

please explain. Frankly I dont see why that should be.

 

I'm reminded of the sentence at bottom of page 3:

"...the deformed Poincare group becomes the usual Poincare group

in the continuum limit where kappa --> infinity."

[jana]

Firstly, keep in mind that unless I explicitly qualify something I post by saying "I know for a fact that..." or "I'm absolutely certain that..." you shouldn't take what I say too seriously since I'm just guessing or giving a preliminary comment, and in fact when I’m discussing papers at this level, I expect that much of what I say will probably turn out to be badly wrong. I guess most of what I post will be sort of "blog-like". Nevertheless, you should of course continue to challenge anything and everything I say whenever you please since for me this is the most stimulating way to learn.

 

However, I know that just because this works for me doesn't mean it makes sense for everyone, and in particular I think that you don't need people to be constantly challenging what you post to have fun, which is of course the whole point of being here: Your an enthusiast who just enjoys following things which for whatever reasons happen to pique your interest at any given time. So unless you say otherwise, I'm not going to spend time trying to find ways to challenge your posts. I hope all of this is okay with you.

 

Okay, so back to your question about what I meant by the remark:

 

It seems to me that for this whole scheme to have any chance of working the energy scale given by kappa must lie below the energy scale at which the first correction to the hilbert action of GR becomes important.

 

My outburst had to do with an impression I got from the last two paragraphs on page 11. It looks like expression (12) depends on the conformal properties of the hilbert action. However, it’s believed to be highly unlikely that this action is exact and should instead be viewed as only an effective theory that is a good approximation at sufficiently low energies. At higher energies higher order interactions consisting of various derivatives of the curvature can be expected to contribute and these will ruin the simple multiplicative scaling behaviour of the action under conformal transformations which the argument for (12) seems to rely on.

 

So consider the energy scale E at which the lowest order such correction becomes important. Now, in geometrized units kappa has units of inverse energy. So (12) seems to require that 1/kappa < E. I guess even if this is true, I’m not sure that this is a problem. I’ll think about it some more.

 

Edit: On a related matter, something I do know is that LQG must assume that the hilbert action truly is exact, which from what I understand is the main reason why people don't believe in it. In other words, the elegance of LQG is a result of viewing the gravitational interaction as being simpler than it actually is.

[jana]

Ahh!!! Barton zwiebach's book just showed up! I'm so excited! Sorry, just had to share.

 

Edit: The book is beautifully bound, smells nice, and uses that heavy, slightly shiny high grade paper cambridge uses for many of their textbooks. I wish they would do the same for their monograph series since they charge even more for them.

[blike]

You mean on an ad? What's the name of the book?

[jana]

I meant that I just took delivery of it. It's called "A first course in string theory" and is aimed at undergrads.

[blike]

Aha I see

 

What level of education do you have? Are you an undergrad? If so thats some serious discourse you're having.

[jana]

I'm going into my final year. But since canadians go to university one year later than americans, many senior courses are really at the graduate level. In fact it's common to see both undergrads, and graduate students coming from universities outside of canada taking the same courses.

[Martin]

So consider the energy scale E at which the lowest order such correction becomes important. Now' date=' in geometrized units kappa has units of [b']inverse[/b] energy. So (12) seems to require that 1/kappa < E. I guess even if this is true, I’m not sure that this is a problem. I’ll think about it some more.

 

I like your vigorousness in reading the article (and sympathise in that respect) but I think you may be confused about something very simple.

 

Your equation (12) is on page 11, right?

On page 11 kappa has dimension of an inverse length-----or an energy, units permitting.

 

You say kappa is an inverse energy.

-----------------

but in an earlier post you spoke of kappa as an energy

and said that for things to work it had to be small

-----------------

now you are saying it is an inverse energy and for things to work

1/kappa has to be small

 

------------------

neither of your interpretations seem consistent

but if you formulate a consistent one i'll try to understand.

 

again I point you to page 3 where kappa is (as usual) an energy i.e. an inverse length (in geometrized units)

and where kappa has to be big, not small, to get the classical limit

 

of course i could be mistaken too---in any case hope you can sort the confusion out

[Martin]

Edit: On a related matter, something I do know is that LQG must assume that the hilbert action truly is exact,...

 

could you give a source please?

this piques my curiosity because it is at odds with what I know of LQG

[jana]

kappa has dimension of an inverse length

 

Oops. Then the condition should be kappa < E.

 

could you give a source please?

this piques my curiosity because it is at odds with what I know of LQG

 

Try any review of LQG ever written. In fact, my remark is true of all canonical approaches to quantizing gravity, whether the phase space variables are the spatial metric and extrinsic curvature of earlier approaches, or ashtekar's variables as in LQG: The hilbert action with higher order contributions would determine a different and more complicated hamiltonian and therefore different canonical variables.