G+S+EM+W physics to quantum

[timology]

After watching a numerous amounts of documetarys about the string theory, I have understood it but I never quite get the point of combining gravity with the strong, weak N force, and EM.

 

I'm not good at physics by far so maybe you guys can help me with this one. Kinda break it down. Explicate it so a person with 1% physics knowledge would understand.

[Reaper]

If you want the simplest possible answer, the reason they are looking for such a theory because both Quantum Mechanics and General Relativity are incomplete theories. Not only that but they aren't compatible with each other.

 

The main challenge is trying to find a Quantum Theory of Gravity that is consistent with General Relativity, without the singularity solutions. The main problem is that gravity only attracts, and is by far the weakest force.

 

For reference between how strong each force is, the Strong Force has strength 1, EM has strength 1/137, Weak Force has strength 1 x 10^-6, and Gravity has strength 6 x 10^-39.

[CPL.Luke]

out of curiosity can it be concluded that the singularity solutions are actually problematic? I know we think of them as fundamentally un-physical but could that be our own pre-concieved notion?

[timology]

CPL.Luke: thats one of my problems also, I think it was searched upon so much that there was just a reason to make it work. I think it was a very pre-concieved notion becuase everyone just wanted it to work.

 

I know the strength of the forces, but for sakes scientist can't figure out gravity so how can they attempt to combine the two. It never made since in the first place. Here is a clip you can see how the explain it.

http://www.pbs.org/wgbh/nova/elegant/program.html

 

Why should this provoke such a thing as finding a super formula?

It never made sence to attempt this to me. Now it has made people crazy about this string when it can be something that has just become (get pissed if you like) a mistake if you will in physics.

 

Boy I feel strong about this lol

[foodchain]

I don’t understand how the forces are really separated for that matter. I mean we have different wavelengths of light, maybe gravity is just a product of energy acting as a force at a certain wavelength of such. Then again I know close to nothing about physics. Its probably just wave particle duality creating some spin off in my head.

[BenTheMan]

CPL.Luke: thats one of my problems also, I think it was searched upon so much that there was just a reason to make it work. I think it was a very pre-concieved notion becuase everyone just wanted it to work. [...]

Why should this provoke such a thing as finding a super formula?

It never made sence to attempt this to me. Now it has made people crazy about this string when it can be something that has just become (get pissed if you like) a mistake if you will in physics.

 

A few things tim---

 

First of all, I take exception to you stating that strings was a mistake (if you will) in physics. The story is far from complete, and I don't really think you are in a position to make such judgements. I always get pissed when people bash string theory just because they read Peter Woit's or Lee Smolin's book, or for some other unknown reason. The fact is that string theory is the most studied way to understand what happens to gravity at high energies---successes have been made in strings that other approaches to the question cannot claim.

 

Secondly, in regards to unification it is well known that the strengths (except for gravity) of the foces change with energy. So, depending on the energy at which you do your scattering experiments, the relative strengths of the forces that you'll measure are different. From all of the data we've gathered, the forces are all very close together at high energies---if you include something like supersymmetry, the unification is precise to within 1% or so. So you have to ask yourself---if the unification works so well, can it be a coincidence? Or, stated another way, suppose you draw three lines on a piece of paper. Is there any reason that those three lines should meet at exactly one point?

 

I mean we have different wavelengths of light, maybe gravity is just a product of energy acting as a force at a certain wavelength of such.

 

This doesn't explain why gravity would be so much weaker than the other forces. For example, gravity is pulling you towards the center of the earth, right? Well, why don't you fall into the Hell? The reason is that there is another force that is much stronger than gravity---namely electromagnetism. Electromagnetic repulsion, which is 10^30 or so times stronger than gravity saves you.

[foodchain]

This doesn't explain why gravity would be so much weaker than the other forces. For example, gravity is pulling you towards the center of the earth, right? Well, why don't you fall into the Hell? The reason is that there is another force that is much stronger than gravity---namely electromagnetism. Electromagnetic repulsion, which is 10^30 or so times stronger than gravity saves you.

 

Right, but its not as if these various forces seem to only be able to operate independently of one another, as in they interact. I mean there are different scales of photons right?

 

sorry, have to go early...

[BenTheMan]

Right, but its not as if these various forces seem to only be able to operate independently of one another, as in they interact. I mean there are different scales of photons right?

 

I'm not sure if I understand the question properly. Electrons, for example, do not experience the strong force. So, suppose you send an electron through an electric field---the electron carries electric charge, so in a sense it ``feels'' the electric field. Now send an electron through a strong force field (i.e., a field of the strong force). The electron doesn't ``feel'' the strong force because it doesn't carry strong charge.

 

Is this answering your question at all?

[foodchain]

I'm not sure if I understand the question properly. Electrons, for example, do not experience the strong force. So, suppose you send an electron through an electric field---the electron carries electric charge, so in a sense it ``feels'' the electric field. Now send an electron through a strong force field (i.e., a field of the strong force). The electron doesn't ``feel'' the strong force because it doesn't carry strong charge.

 

Is this answering your question at all?

 

Ok, I have a bit more time this time around:D

 

Basically, its just speculation on my behalf, so don’t get uptight as I am not trying in anyway to say this is how it is in reality, simply put I only hold barely working knowledge of biology really.

 

I think of the big bang, which from what I understood came to a point in which quarks came about, and then to another point in which quarks could more or less coalesce into matter. So how did mass come about, to me it operates with gravity, or interacts with such, but so can light which is mass less, and of course "dark" matter or "dark" energy. Personally, I just don’t understand it to the point that I can feel comfortable saying that this is a separate entity, and this is a separate entity. So for me, I question the reality that if everything is fundamentally related, that if physical phenomena is not just a product of the available spectrum of physical activity such can express. Such as light, EM in general, or gravity, if they are not all just products of energy in a reduced tone in my opinion basically existing.

 

How could energy differentiate into such forms, if not for such forms being a running product of the environment, which again leads back into a loop in my opinion on how energy differentiated in the first place. I mean going from conservation laws, the differentiation can make some sense to my mind, but I am sure its nothing close to the truth. Its just when it comes to gravity, I don’t understand why it shares such a separation with other phenomena, such as being something outside of other quanta for instance, or for that matter why elements decay in the first place, as you can probably see from reading this I am all over the place when it comes to this subject, and to be honest its made me stay up many nights.

[Severian]

The fact is that string theory is the most studied way to understand what happens to gravity at high energies---successes have been made in strings that other approaches to the question cannot claim.

 

That is debatable. Since string theory has made no testable predictions we don't know whether or not it has anything to do with gravity whatsoever.

 

 

From all of the data we've gathered, the forces are all very close together at high energies---if you include something like supersymmetry, the unification is precise to within 1% or so. So you have to ask yourself---if the unification works so well, can it be a coincidence?

 

I hear this argument a lot (it seems to be John Ellis' favourite) but it is a little surprising. In principle, one expects effective higher dimensional operators coming from some GUT scale physics, so they are suppressed (for dimension 6 operators) by [math]Q^2/M_{\rm GUT}^2[/math] (where Q is the scale we are working at) and we can ignore them at low energies. But near the GUT scale one would expect them to become important, and affect the running. IIRC Graham Ross(?) wrote a paper on this quite recently. The fact that the SUSY couplings meet at the GUT scale is actually pretty weird. (To my mind this is still an argument for SUSY, and is probably telling us that the GUT physics is (almost) conformal.)

[BenTheMan]

That is debatable. Since string theory has made no testable predictions we don't know whether or not it has anything to do with gravity whatsoever.

 

It's really not debatable. The fact that there are people (like me) getting very realistic low energy phenomenology out of string theory (three generations, heavy top, realistic higgs sector...) says quite a bit.

 

In principle, one expects effective higher dimensional operators coming from some GUT scale physics, so they are suppressed (for dimension 6 operators) by (where Q is the scale we are working at) and we can ignore them at low energies. But near the GUT scale one would expect them to become important, and affect the running.

 

This is actually something I've in mind to look at. The usual calculations of these threshold effects only give small contributions to the runnings below the threshold. The consensus is that corrections of about 1% are expected---this is why unification in the standard model was so hard to get.

 

====\begin{edit}

http://arxiv.org/PS_cache/hep-ph/pdf/0411/0411057v1.pdf

I just looked at a Graham Ross paper, perhaps not the one that you were talking about, where he concludes that the threshold corrections improve unification, when starting with the weakly coupled heterotic string. But the consensus among traditional GUT physicsts (i.e. my advisor) is that the threshold corrections won't screw up unification.

====\end{edit}

 

(To my mind this is still an argument for SUSY, and is probably telling us that the GUT physics is (almost) conformal.)

 

This is also interesting, and another thing I'd like to look at. Maybe I should stop talking to you before I give away all of my research ideas:)

[timo]

The fact that there are people (like me) getting very realistic low energy phenomenology out of string theory (three generations, heavy top, realistic higgs sector...) says quite a bit.

But that's all part of the SM already so it does, in my eyes, not contribute to testable predictions (it's rather a sanity-check). For these, there had to be a testable feature that is not part of the SM. A testable prediction would be something in the lines of a Z' peak in ILC-range (which then had to compete with other models proposing Z' peaks).

As a matter of fact, "testable" strictly speaking goes down not only to the level that something different from the SM must happen but also that it must be measurable experimentally. I remember that some time ago Martin advocated a paper on black hole production at LHC claiming it was a testable prediction for LQG. Incidently and uncorrelatedly, around the same time (same week) I had a Skype conversation with the guy I shared the office with who was in ... think it was Belgium ... at that time. He told me that he had lunch with some phenomenologists (the kind of pheno people that actually work together with the experimentalists) who were making fun of black hole production at LHC because it gave no distinguishable signal in the detector (e.g. no preferred direction of energy disposition).

Now, I neither claim to have enough knowledge of either strings or lqg or even experimental physics. I just wanted to point out that the understanding of the term "testable prediction" might differ from person to person. And to grab a seemingly widespread prejudice: Stringers are notorious for having a very lax understanding of the term.

 

 

A question on gauge coupling unification:

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

Do the couplings of "pure SUSY" (whatever that would mean, say the particle content of the MSSM) actually meet at the GUT scale? I always see these statements in conjecture with sidenotes saying "if you consider a GUT-factor of ..." ... errr ... I think it is "3/5". Do the couplings meet in SU(5), in SO(10), in all GUTs (not sure how many there are) or is it really a general feature of SUSY alone?

Or asked the other way 'round: What does the statement about the GUT factor (e.g. in the SUSY-primer by Steven Martin at the place where the graph with the meeting couplings is shown) mean? Making three lines meet by shifting one is not that much of a trick from a purely geometric point of view (although admittedly the factor might come from somewhere else and not from the demand to make the lines meet).

[Martin]

...some time ago Martin advocated a paper on black hole production at LHC claiming it was a testable prediction for LQG...

 

I hope you realize that I did not claim that any kind of LQG predicted black hole production at LHC

 

My argument was the opposite. non-string QG theories usually assume 4D with NO EXTRA DIMENSIONS, so they would be shown to be wrong if there was credible evidence of extra dimensions.

 

In that sense if there was some kind of

BH observation that served as evidence of extra dimensions you could say that it falsified LQG----at least as the theory stands, in usual 4D version.

==============================================

 

Atheist,

Except for your seeming to have misunderstood or misrepresented something I said, I wholeheartedly agree with your main point:

 

But that's all part of the SM already so it does, in my eyes, not contribute to testable predictions (it's rather a sanity-check). For these, there had to be a testable feature that is not part of the SM.

 

... not only to the level that something different from the SM must happen but also that it must be measurable experimentally.

 

"Sanity-check" is a good term for that kind of checking for consistency with past results.

 

But a self-respecting theory has to do more than just "post-dict" the observed results of past experiments. It has to risk being falsified by predicting the unknown outcome of a future experiment.

 

For practical purposes the easiest way to keep the concepts straight is just to remember that testability means falsifiability (a theory that can accept any possible outcome of a yet-to-be-performed experiment is not predictive---it should bet its life on some prediction so that if it fails, it's out.)

 

In line with this, it's reasonable to require any theorist be able to answer the question "Describe a possible new experiment such that if the outcome were different from what your theory predicts, you would give it up and work on something else."

[timo]

Errr .... let's say "now that you mention it, yes I remember" . So thx for reminding me of which way round it was. Doesn't change the problem that if BH production can indeed not be measured and detected/determined experimentally it's not a test, neither a test for predictions nor a falsification test.

[Martin]

My point was IF as the paper asserted some evidence for extra dimensions might be produced at LHC, then that would tend to falsify 4D quantum gravity.

 

I don't believe in extra dimensions or that the LHC will provide evidence pointing to their existence.

 

But IF, for the sake of argument, extra dimensions WERE somehow detected then I expect quite a bunch of LQG people would abandon their line of research.

[fredrik]

Perhaps another interpretation of the question but...

 

I never quite get the point of combining gravity with the strong, weak N force, and EM.

 

I think it's for the same reason we bother finding theories for any observation. Why not just file all the data anyone ever made in a gigantic archive, and say that, this is what we know, what's beyond that is speculation?

 

Some obvious problems with that approach is that first of all the information capacity required would quickly get overwhealming. So we would have no choice to but discard data - or GROW lager memories! and how do you do that? it can be done, but it's not like instant noodles - due to limited information capacity. Thus facing reality, we should make sure that we dicard the least valuable information, because information capacity is limiting. The most crude way to do it, is to keep only the raw data that we think is most relevant in some sense. But a more advanced way is to actually process the data, and effectively accomplish a data compression, with a minimum information loss. Thus we can store more information with less storage capacity.

 

Also, a living organism, human, or I figure even a particle, has to do processing, and make choices on how to respond to reality, given the limitations. Two limitations are information capacity and processing capacity.

 

Similarly, more advanced processing should suggest, along with finding theories that allow data compression, finding theories of theories that allow compression of theories. Because the theories themselves take up some memory, and also processing power. Like in comp science, more efficient compression algorithms usually take longer time to decode and encode. So you sort of transform "information capacity" for "processing time".

 

Simplifications and finding more fundamental principles, and more efficient representations for the benefit of increased fitness of responding to the environment is I think one of the fundamental issues in nature. I think it applies to physics as well as biology.

 

/Fredrik

[BenTheMan]

But that's all part of the SM already so it does, in my eyes, not contribute to testable predictions ... Stringers are notorious for having a very lax understanding of the term.

 

The point was that people have been getting very realistic phenomenology from string theory since the mid eighties, when the heterotic string was discovered. As far as I know, these ``sanity checks'' aren't as easy in LQG, but I could be mistaken about this. (And, to be fair, I never claimed that string theory gave testable predictions.)

 

Or asked the other way 'round: What does the statement about the GUT factor (e.g. in the SUSY-primer by Steven Martin at the place where the graph with the meeting couplings is shown) mean? Making three lines meet by shifting one is not that much of a trick from a purely geometric point of view (although admittedly the factor might come from somewhere else and not from the demand to make the lines meet).

 

I'm not sure what you're talking about here---let me look at the copy of Martin's paper I have in my office.

[Doctordick]

Hi fredrik, you couldn't be the same character I am talking to elsewhere could you? I have been reading your posts and they seem quite rational. I thought I might just comment on this one.

Why not just file all the data anyone ever made in a gigantic archive, and say that, this is what we know, what's beyond that is speculation?

 

Some obvious problems with that approach is that first of all the information capacity required would quickly get overwhelming. So we would have no choice to but discard data - or GROW lager memories! and how do you do that? it can be done, but it's not like instant noodles - due to limited information capacity. Thus facing reality, we should make sure that we discard the least valuable information, because information capacity is limiting.

It should be clear to you that, whatever theory is put forth, it is clearly influenced by “undiscarded” information only: i.e., you have the cart on the wrong side of the horse (so to speak). Any theory must be established by information available; anything else is simply beside the point.

The most crude way to do it, is to keep only the raw data that we think is most relevant in some sense. But a more advanced way is to actually process the data, and effectively accomplish a data compression, with a minimum information loss. Thus we can store more information with less storage capacity.

This is an excellent observation. It seems to me that you are seeing “current theory” as a data compression mechanism which is an excellent perspective.

Also, a living organism, human, or I figure even a particle, has to do processing, and make choices on how to respond to reality, given the limitations. Two limitations are information capacity and processing capacity.

(It was this line that made me think you were the person I was talking to: "even a particle".) But, back to your statement: in essence, this is not a fundamental issue at all; it is merely a statement concerning the complexity of the solutions obtainable by that living organism (a matter rather different than the problem being talked about).

Similarly, more advanced processing should suggest, along with finding theories that allow data compression, finding theories of theories that allow compression of theories. Because the theories themselves take up some memory, and also processing power. Like in comp science, more efficient compression algorithms usually take longer time to decode and encode. So you sort of transform "information capacity" for "processing time".

 

Simplifications and finding more fundamental principles, and more efficient representations for the benefit of increased fitness of responding to the environment is I think one of the fundamental issues in nature. I think it applies to physics as well as biology.

I like your perspective quite a lot. We might really be able to communicate.

 

Have fun -- Dick

[fredrik]

Hello Doctordick, yes I'm the same one indeed I'll respond later, as I mentioned before I try to do some other stuff as well so I deliberately try to keep the pace of communications down a little.

 

It should be clear to you that, whatever theory is put forth, it is clearly influenced by “undiscarded” information only: i.e., you have the cart on the wrong side of the horse (so to speak). Any theory must be established by information available; anything else is simply beside the point.

 

The reason I consider the concept of discard is that, there is not other choice! A particle beeing bombarded with radiation simply can't absorbd and keep that energy arbitrarily, some of it's reemitted with a delay or reflected. Also consider yourself when you try to learn, when your brain gets saturated, you need to develop a better strategy. Anyway "discard" is just a word, and perhaps a bad one. It's not like it's a _choice_ to discard, it's a constraint from limiting information capacity.

 

Information available to whom, me, you or some god? and can this subject simply harbor unlimited amount of information? If not, the issues needs solution. There is a clear potential in this approach. Understanding physical interactions as communication may provide (I personally think at least) deep insight to reality.

 

/Fredrik

 

It seems to me that you are seeing “current theory” as a data compression mechanism which is an excellent perspective.

 

Yes, that is a decent way of putting it. So the question, is what the best data compression mechanism is? Usually different kinds of data, may be _best optimized_ by certain algorithms. This is why pure reason alone, can not tell us the answer, we need real data. And the theory is bound to be a dynamic entity, responding and morphing to a "data stream". What I focus on, is the logic and physics of the relation between the input, updating the theory, and output...

 

As you also noticed some parts of this contains something like a chicken/egg situation, that is exactly why I come to think that the solution is a relational and evolutionary. So there is not unique objective starting point, all we can hope to see is the transformation of states, relatively speaking.

 

But, this will be interesting to noone until it's done. Until then, it will look just like philosophy and baloney. If you get someone on the same page, it might be able to communicate with reasonable effort, otherwise "on your own" is the most efficient way I think.

 

/Fredrik

[Doctordick]

Hello Doctordick, yes I'm the same one indeed

Well, that's nice; I then take it to indicate your understanding of mathematics is probably better than the average. I would very much like to get you interested in examining my logic. Meanwhile, not to take up your time but rather to clarify some of my earlier comments on this thread which I think you misunderstood.

Yes, that is a decent way of putting it. So the question, is what the best data compression mechanism is?

What I meant was that all “theories” are themselves data compression mechanisms. Their central purpose is to provide one with a replacement for that “gigantic archive” you mentioned.

Why not just file all the data anyone ever made in a gigantic archive, and say that, this is what we know, what's beyond that is speculation?

The theory allows you to discard massive amounts of that archive. One problem is, if the theory is flawed in some way, the discard might include things which should not have been discarded. (By flawed I mean that data in that discarded data could have have been used logically to impeach the theory). You see there is another issue here; not only are we unable to maintain the archive you refer to but we do not even have the capability of totally examining all the possibilities of the average theory against the archive it rests upon before we discard that actual information the theory is to reproduce. Our out is that we commonly assume future results will bring out that error if that error does indeed exist; however, that is clearly an assumption (and a bad one at that).

 

The only intelligent out is to come up with a mechanism for assuring the theory is flaw-free; finding a way of implementing that requirement is a rather serious issue which one would think would interest any objective scientist.

The reason I consider the concept of discard is that, there is no other choice!

True, there is no other choice; however, presuming one must discard data prior to considering what constraints should apply to your theory is a rather extreme approach. One should at least examine the idea of creating a flaw-free theory from a archive which is handleable. That was one of the points I was trying to bring up.

It should be clear to you that, whatever theory is put forth, it is clearly influenced by “undiscarded” information only: i.e., you have the cart on the wrong side of the horse (so to speak). Any theory must be established by information available; anything else is simply beside the point.

Until you can comprehend a method of creating a flaw-free theory from a small amount of information, you certainly should not go around discarding information. You should first solve that serious problem.

It's not like it's a _choice_ to discard, it's a constraint from limiting information capacity.

But you are using it to avoid thinking about the problem of creating that flaw-free theory. Certainly, discarding information which would invalidate the theory if kept is not a proper scientific procedure.

Understanding physical interactions as communication may provide (I personally think at least) deep insight to reality.

Here again you have grasped the wrong intent from my comment about communications. What I was trying to point out is that the very issue of understanding a language constitutes a theoretical solution to the problem of meanings and relationships. You have in your mind, a subconscious solution to the meanings of the symbols comprising that language. That theory was arrived at through several years of data interpretation (involving much data discard) and you cannot be sure your understanding is flaw-free. Why do you think languages change with time? Every generation interprets the symbols a little differently; it is actually as dynamic a process as is any.

What I focus on, is the logic and physics of the relation between the input, updating the theory, and output...

But you cannot update a theory you don't have. How do you set one up initially? If one wants to do hard science, that is the problem you need to solve first. Anything else is just a “guess and by golly” approach submitted to nature to be gleaned by evolutionary forces.

So there is not unique objective starting point, all we can hope to see is the transformation of states, relatively speaking.

So, the starting point of complete ignorance does not exist and never existed? What did the first inkling of understanding start with? Are you saying GOD handed it down as a given thing? If not, it has to start from a very specific situation: “the problem becomes one of constructing a rational model of a totally unknown universe given nothing but a totally undefined stream of data which has been transcribed by a totally undefined process”. I say that is the unique objective starting point and the scientific community's refusal to look at it is a religious bias.

But, this will be interesting to no one until it's done.

Is that to be taken to mean you are no longer interested? That would sort of end this exchange wouldn't it. For your information, it's already been done; I did it over forty years ago.

Until then, it will look just like philosophy and baloney.

To me that sounds an awful lot like a religious defense of a refusal to look. If that is really the case (and I hope it isn't), I can only say that ignorance is its own reward and I am sorry to lose you.

 

(I'll probably be banned from this forum for this but I really don't think it really makes any difference.) The powers that be immediately locked the last thread I posted to less than an hour after Severian's posted a succinct intellectual rebuttal of my logic (which I am sure is the position the academy would back):

“The only 'significant fact' that I am able to deduce from your "deduction" is that you are a complete and utter moron.”

I suppose that was so I could not point out the errors in that post. My last comment before the lock was:

Anybody want more? I can give you lots more if you are interested.

I think they were afraid someone might have been interested.

 

It has been fun -- Dick

[fredrik]

But' date=' this will be interesting to no one until it's done.

[/quote']

Until then' date=' it will look just like philosophy and baloney.

[/quote']

Is that to be taken to mean you are no longer interested? That would sort of end this exchange wouldn't it.

 

Those comments was meant to be in defense of those who disagree with me

 

I don't think it's as simple as: if someone doesn't understand me - they are ignorant, or I am stupid. Communication is a mutual thing, and I really DO understand that people who come from another view, does not make sense out of my ideas. Why would they? Also, how much can I expect anyone else to "invest" in trying to understand my little ides? I expect nothing of noone, I was just trying to be a little humble, to keep a good atmosphere, and say that I have an understanding even for those who disagree and doesn't see what I mean. I don't understand everybody elses thinking either, but that's part of reality. But I sure can understand that who parties/humans/particles can disagree, without necessarily one of them beeing stupid, or flawed.

 

Yesterday I didn't get around to anything. Hang on.

 

I'll avoid elaborating on my on thinking here, beucuse it's not ready for explaning in details and ther are many complications, and this thread isn't the right place. It was just meant as comments to compare with your ideas. We can resume our discussions in the other place later, so we don't trash this thread.

 

/Fredrik