Sunday, October 10, 2010

Cosmic Strings

The appeal of string theory is in the simplicity of the idea. The devil, as usual, is in the details that follow. But one-dimensional objects are common in physical systems, and sometimes have little to do with string theory as the candidate theory of everything. The Lund string-model for example is an effective description for the fragmentation of color flux-tubes resulting in hadronization. And then there's cosmic strings.

Cosmic strings are stable, macroscopic, one-dimensional objects of high energy density that might be created in the early universe. It was originally suggested by Kibble in 1976 that such objects could form from symmetry-breaking phase transitions in quantum field theory that would take place when the universe was young and hot. These strings then form a network of (infinitely) long strings and loops that evolves with the expansion of the universe. It was thought for a while that strings might seed the density perturbations leading to the large-scale structures we see today, but this turned out not be consistent with the increasingly better data. While we know now that cosmic strings cannot have dominated in the early universe, some of them might still have been present, and still be present today.

The topic raised to new attention when it was found that cosmic strings might alternatively also be created in a string theory scenario in the early universe and then grow to macroscopic sizes. That is interesting because cosmic strings have a bunch of possibly observable consequences. For the purposes of testing string theory, the question is of course if one could distinguish a cosmic string created by ordinary quantum field theory from a cosmic super-string-theory-string.

Two of the most outstanding observables are that cosmic strings create peculiar gravitational lensing effects and can, while they move around, create cusps that release bursts of gravitational waves. There are other, more subtle, signatures, such as the creation of small non-Gaussianities in the cosmic microwave background (CMB) and some influence on the CMB tensor-modes, but the gravitational lensing and gravitational wave bursts have so far gotten the most attention due to the already good experimental prospects of detecting them.

For what the lensing is concerned, every now and then a candidate is found where the lens might have been a cosmic string, though none of them has survived scrutiny. Like CSL-1, that later turned out to be merely two similar galaxies in close vicinity. In any case, the gravitational lensing wouldn't allow us to tell whether we're looking at a super-string or not.

There are however differences between fundamental and non-fundamental cosmic strings that have been pointed out during the last years. These stem from the presence of additional spatial dimensions in super-string theory. These have the consequence of altering the evolution of the string network, resulting in a denser network today, that might give one the hope that bursts of gravitational radiation are more likely to occur. Recently though, a more detailed study has been done, examining the motion of the string and the gravitational radiation emitted by taking into account the additional dimensions:


In their analysis, the researchers found that the presence of compactified extra dimensions larger than the width of the string dampens the gravitational wave emission. The effect depends on the the number of extra dimensions, and the damping can be several orders of magnitude. While this is interesting in the sense that the signal carries information about the sort of string one is dealing with, it means unfortunately that the signal is also far less likely to be detected at all. The strength of the damping depends also on the ratio of the width of the string and the size of the extra-dimensions, though this dependence is hidden within the model and not obvious from the results. I wrote to one of the authors of the above paper, Ruth Gregory, and was explained that simulating the dynamics of a thick string was quite a challenge which is why they had to resort to an empirical model.

A signal of cosmic strings would be tremendously exciting either way. But so far the prospects of being able to unambiguously assign such a signal to string theory seem slim.

80 comments:

Uncle Al said...

A cosmic string passing through a star would not be a subtle effect. Passing through a black hole galactic core more so. Using galaxies as visual diagnostics, either cosmic strings are non-interactive or are non-existent.

A tangled ball of string(s) coupling galactic rotation vs. radius only via gravitation, as an alternative to dark matter, is sufficiently horrible to be pursued. Fermionic string balls self-inflate.

"When all you have is a BNC feedthrough, all your electrical problems look coaxial."

Robert L. Oldershaw said...

With all due respect, in the absence of supportive empirical evidence, isn't this strings/cosmic strings/superstrings/M-theory stuff just abstract theoretical castles in the air?. In some circles such reasoning is quite fashionable, but to me and many other scientists it seems like pure speculation and sounds more than a little far-fetched. Maybe like an Aristotelian astronomer touting the elegance and power of epicycles.

Peter Woit's excellent book "Not Even Wrong" should have been a sufficient corrective.

Bottom line: Where's the science?

Bee said...

Robert,

That's why we're looking for evidence. Best,

B.

Phil Warnell said...

Hi Bee,

Please correct me if I have this wrong, yet basically what you`re saying is even if the existence of Cosmic Strings are confirmed, that this in itself doesn`t support string theory as being a viable theory. That is cosmic strings being phenomena that are contained in other theories. Okay then, what implications are there for current QG models or existing established theories if the presence of such phenomena is ruled out via observation at some point? That is I would hope that the presence or absence of such phenomena reveals something about the form and workings of nature otherwise I'm totally confused; not that this would be the first time however:-)

Best,

Phil

Steven Colyer said...

I second all of Oldershaw's motions and propose the topic be opened to public debate.

Hi Bee,

In the body of the post/article/blarticle (indeed the first sentence)you wrote:
The appeal of string theory is in the simplicity of the idea.

Which reminds me that half a century ago that the appeal of Gamow and Alpher's Ylem was in the simplicity of the idea. (And before that Earth, Wind, and Fire (and Air), and before that Marilyn McCoo and Billy Davis and The Fifth Dimension singing "this is the dawning of the age of Aqiuarius", etc. Ah, the 60's. Every decade since has been dull in comparison).

Speaking of "dimensions" (a word that has a slightly different definition depending on whether you're talking Math or Physics), THAT is the appeal of String Theory, playing with multiple ones more than the 3 dimensions of space and the 1 of time that we're sure exist. It's fun, no doubt, and doubly useful for people like Susskind who wish to keep the (unfalsifiable) debate going for the rest of their lives, as Professors Emeriti do draw salaries, yes? Among other reasons, but of course. Far be it for me or anyone else to imply that's the main reason.

It is far, far easier to prove something right that to prove something wrong, at least in Maths, and that is what SuperDuperStrings basically are.

Ruth Gregory's defense is quite telling. What I got from your post Bee is that yes, these things may exist, but thanks to multi-dimensionality, we can't detect them, so nyah nyah, prove us wrong. Pfft.

Zephir said...

"Cosmic strings" are just one of many misconceptions of string theory. These things were actually observed already as a streaks of dark matter, connecting the galaxies.

http://www.mpa-garching.mpg.de/HIGHLIGHT/2002/fig0206_1.jpg

The same is true about extradimensions (they're all around us) and other concepts, not so specific to string theory (AdS/CFT duality, supersymmetry, etc.)

Christine said...

Exactly what is the mechanism in a symmetry-breaking phase transition that favors the creation of high density 1D objects in contrast to, say, 2D or 3D objects?

Steven Colyer said...
This comment has been removed by the author.
Steven Colyer said...

Christine asks an excellent question, to which I would add: What do the world's top Loop Quantum Gravitationists and Causal Dynamical Triangulationistss say about all this.

Where's Carlo Rovelli and Renate Loll when you need them?

And what of Martin Bojowald? What does he think of this stuff?

Zephir said...

During condensation of dense supercritical gases the speed of energy spreading should be lowest during formation of nested supercritical phase, composed mainly of nested 3D spheres.

http://superstruny.aspweb.cz/images/fyzika/aether/supercritical1.avi

I presume, the 3D structures are most probable, because just 3D hyperspheres exhibit the highest volume/surface ratio, thus enabling the formation of most compact Universe.

http://mathworld.wolfram.com/HyperspherePacking.html

Therefore the observable structures inside of 3D Euclidean Universe are mostly 3D, just after then 2D or 1D... Most galaxies are formed with flat 2D rings, only subtle streaks between them are formed with subtle 1D "strings".

We can simply ask, which objects will be most frequent inside of random Boltzmann gas, where energy is spreading in slowest possible way? This is quite relevant question for mathematicians and it can be answered with particle simulations without any deeper math, too.

Zephir said...

Here you can find a computer simulation of strings in five dimension as a consequence of Gregory-Laflamme instability

http://prl.aps.org/abstract/PRL/v105/i10/e101102

Due the presence of extradimensions, the gravity collapses these artifacts into strings in similar way, like the polymer strings are coalesce into dropplets.

http://www.chemie.uni-hamburg.de/tmc/clasen/research/research_e.html

Such polymers are formed with stringy fluid, similar to those predicted with Kipp Thorne's membrane paradigm for description of black hole interior before years.

Compare the result of these simulation with models of dark matter at cosmic scales.

http://www.mpa-garching.mpg.de/HIGHLIGHT/2002/fig0206_1.jpg

The dropplets of galaxies hanging on strings are clearly apparent there.

Zephir said...

I presume, these dark matter noodles are actually equivalent to worm holes and Einstein-Rosen bridges, predicted before years at the same moment - they're all the same objects, like dark strings and dark matter streaks everything was already observed there. These mathematically clean, but hyperdimensional objects just appear a bit voluminous and fuzzy from our low dimensional perspective.

It basically means, mathematicians have good & relevant ideas - they're just unable to see them in everyday reality, because their view is idealized.

Zephir said...

/* Additional dimensions both round off cusps, as well as reduce the probability of gravitational waves formation*/

Regarding the influence of dark string to gravitational wave spreading, my stance is exactly dual.

As you probably know already, in dense aether theory the gravitational waves are longitudinal and superluminal - so they're forming CMB noise in analogy to spreading of underwater sound waves along water surface (do you see, how longly sought artifacts were observed already, again?). Because underwater waves are always faster, then the surface ones, they will spread at the surface like noncausual noise and we will detect nothing periodic here.

Because of massive influence of extradimensions, every harmonic component of gravitational waves will be dimished to zero and we are detecting only CMB noise. Actually there is a weak posibility, the oriented streaks of dark matter will serve as an analogy of underwater SOFAR channel for sound spreading, thus making the detection of harmonic waves at the large distance easier.

So, if we're really expecting, we will detect some periodic component inside of CMB noise, then the 1D strings could actually help us - not prohibit us in such detection.

Steven Colyer said...

Sheesh, Zephir, Bee really hit a chord with this post with YOU, hmm? Talking about "noodles", you really used yours.

Thanks a lot, Zephir, and I mean this in a good not sarcastic way, you just gave us a week's worth of stuff to investigate.

I like the way you ended the third of your quadruple-reply, and wish to present an example, and your thoughts would be appreciated.

You wrote:
It basically means, mathematicians have good & relevant ideas - they're just unable to see them in everyday reality, because their view is idealized.

Here's my example: Quantum Entanglement. It only works over the distance of kilometers, or miles, as experiments in Geneva have confirmed (and no Engineer such as myself is surprised, because "the real world" kinda gets in the way of "theory").

PURE Quantum Entanglement is kinda screwy that way, and would probably work, IF AND ONLY IF the two entangled particles were the only two particles in the Universe. Really cool stuff if so, but as we all know, there are more particles in the universe than ... two. Interference and Decoherence really DO exist, and saying that just opened me up to a verbal spanking by Neil Bates. :-)

Rhys said...

Christine, that's a good question. It also has a good answer, but it's necessary to have a bit of knowledge of topology and group theory, or to sit down and draw diagrams for a while (not possible here!).

Basically, it depends on what the broken symmetry is. Strings form when, for example, the broken symmetry group is the group of rotations of a circle. For a different example, you have probably heard of monopoles. These are point-like objects (zero-dimensional), as opposed to strings, which form when a different type of symmetry breaking occurs. The final possibility in three dimensions is domain walls, which are two-dimensional objects which can form when a discrete symmetry is broken.

(Let me also say that, as far as I could tell from quickly skimming his/her comments, Zephir hasn't made a single statement which is both relevant and correct.)

Bee said...

Zephir:

Do you actually read the articles from which you post pictures? The picture you have in your first comments is, I think, simply dark matter filaments resulting from normal ΛCDM structure formation. It has nothing to do with cosmic strings whatsoever. Best,

B.

Bee said...

Zephir:

Regarding your later comment, the "dark matter noodles" have nothing to do with wormholes or Einstein-Rosen bridges either. What is shown in the picture is basically matter density. Wormholes are something completely different, they have a non-trivial geometry. You're reading too much into pictures. I'd suggest you look at some equations every now and then. Best,

B.

Bee said...

Hi Steven,

Well, what one finds appealing is of course personal taste, but for what I am concerned, the extra dimensions are not appealing. The whole landscape-issue stems from there if you think about it. Best,

B.

Bee said...

Hi Christine,

That's an excellent question indeed. I would guess that 2+1 dim objects are not stable and would decay to 1+1 dimensional ones, but to be honest I don't know. Best,

B.

Bee said...

Hi Phil,

You don't need string theory to create cosmic strings per se, thus their existence alone would not be evidence for string theory. What I've tried to explain however is that the cosmic strings in string theory are different. The question is whether one can find an observable that allows one to pin down the difference. As it presently looks, it's not impossible but very unlikely. But who knows, something else might be proposed. Best,

B.

Bee said...

Hi Steven,

"What I got from your post Bee is that yes, these things may exist, but thanks to multi-dimensionality, we can't detect them, so nyah nyah, prove us wrong. Pfft."

I think you misunderstood the point. What I was explaining is that string theory's additional dimensions make a difference for the signature. That's the good news. The bad news is that that difference is such that the signal is unlikely to be detected to begin with. That's what happens if you do a calculation, the result isn't always what you wished for. But either way, nyah, nyah, pfft isn't really an appropriate reaction to what I think is a very interesting study in the right direction. Best,

B.

Bee said...

Hi Rhys,

Thanks for the explanation :) Best,

B.

Plato said...

Definitively a subject hard to wrap one's head around unless "pictorially" we can see some of it's reference?

Thanks for the historical Bee. Some info to add.

Just some thoughts and quotes back to 2005.

One such field, called the dilaton, is the master key to string theory; it determines the overall strength of all interactions. The dilaton fascinates string theorists because its value can be reinterpreted as the size of an extra dimension of space, giving a grand total of 11 spacetime dimensions

According to T-duality, universes with small scale factors are equivalent to ones with large scale factors. No such symmetry is present in Einstein's equations; it emerges from the unification that string theory embodies, with the dilaton playing a central role. Gabriele Veneziano



Update on Cosmic Strings


Joseph Polchinski, KITP, UCSB: Update on cosmic strings

Plato said...

Cosmic Strings Revisited

http://astro.uchicago.edu/~andrey/talks/Planetarium03/s01.png

Lens candidates in the Capodimonte Deep Field in vicinity of the CSL1 object by Sazhin M.V.1, Khovanskaya O.S.1, Capaccioli M.2,3, Longo G.3,4,Alcal´a J.M. 2, Silvotti R.2, Pavlov M.V.2

Plato said...

Cosmic Strings & other Topological Defects

What are topological defects?

Topological defects are stable configurations of matter formed at phase transitions in the very early universe. These configurations are in the original, symmetric or old phase, but nevertheless they persist after a phase transition to the asymmetric or new phase is completed. There are a number of possible types of defects, such as domain walls, cosmic strings, monopoles, textures and other `hybrid' creatures. The type of defect formed is determined by the symmetry properties of the matter and the nature of the phase transition.

Plato said...

High-Resolution Cosmic String Simulations

Don't forget to check out the numerical simulations

Steven Colyer said...

Bee, I'm not sure if any extra dimensions other than the 3S+1T dimensions we're SURE OF exist, and neither is anyone else.

I am however willing to consider one extra spacial dimension, in which we are embedded, such that in any direction we look, we can't tell ... yet.

Rather than consider all these "compactified" dimensions smaller than us, have any of you geniuses (which you are) stopped to think, consider, and publish, that WE ARE are the compactified dimensions?

Bee said...

Hi Steven,

I cannot make any sense out of your question. "We" are to best present knowledge quarks, electrons and the respective gauge fields. A dimension is a global feature of spacetime. You can make its radius position dependent if you wish (I'm sure there's papers on that), but that's a scalar field, and we know matter is fermionic. In summary, I have no clue what you are talking about. Best,

B.

Steven Colyer said...

We know of 5 fundamental particles that have been experimentally verified and about all else is based: quarks, gluons, electrons, photons, and neutrinos. Let's start from there, shall we?

Uncle Al said...

A cosmic string doubling a galactic image in our telescopes must be massive. Necessary mass looks like ~10^24 kg/km. Earth's mass is 5.97^24 kg, Sol's mass is 1.99x10^30 kg. Black holes, including galactic centers, are cosmic string vacuum cleaners. Cosmic string prevalence plus extension must create black hole anomalies.

The sky would be sparkles as black holes' event horizons played crack-the-whip with progressively ingested cosmic rings, also emitting gravitational waves. Presumed cosmic string diameters of 1 fm or smaller, or zero width re Nambu-Goto approximation, don't fix that.

Where are the anomalies?

Christine said...

Rhys,

Thanks for your outline!

For an astrophysics/cosmological perspective, I've just seen that a good material is in Borner's book "The Early Universe: Facts and Fiction" (mine is the 1988 edition; at amazon I've found out that there will be a new edition soon), section 6.7, page 206.

There one can learn that there is a close analogy for the description of how these topological objects arise in 1D, 2D and 3D in comparison with the physics in magnetic-flux vortices in type II superconductors.

Domain walls in particular would either lead to catastrophic collapse or to inconsistencies in our present-day observations, so these are unlikely to exist, according to that reference.

Best,
Christine

stefan said...

Dear Christine,


as Rhys has explained, the essential point is to look at the homotopy classes of vacuum configurations after symmetry breaking, or more specifically, at the homotopy classes of mappings from space minus the defect to the possible field values the vacuum can take - for example, a value at the bottom of the mexican hat potential, i.e in U(1). If there is more than one such class, defects are possible.

As "space minus a line defect" is topologically equivalent to U(1), the relevant homotopy classes for symmetry breaking into the minimum of the Mexican hat potential are the mapping classes of U(1) to U(1), i.e. the fundamental group (the first homotopy group). These classes are characterized by the integer winding number, which can differ from zero, and hence, line defects can exist.

In the case of the cosmic strings, I am not sure which symmetry actually is broken (Sabine and I discussed about that yesterday - there are many options, depending on the model used...), but a good candidate is the axial U(1) (which has the gamma_5 in the exponent).

In an analogous way, to see if point defects, or wall defects are possible, on has to look at the zeroth or second homotopy groups...

My "Ryder" is currently stored away in a moving box, but if I remember correctly, the topological classification of defects is discussed in this book. And for more technical details, I had once looked into "Topological structures in field theories" by P Goddard and P Mansfield, Rep. Prog. Phys. 49 (1986) 725, especially section 3, "Ideas from topology". This is quite cool stuff!

Cheers, Stefan

stefan said...

Dear Christine,

ah, our comments crossed... my Börner is stored away also ;-)... Cheers, Stefan

Christine said...

Dear Stefan,

Thanks for your comment and references!

(Indeed, I see that Ryder's chap. 10 is on "Topological objects in field theory". I'll take a look opportunely.)

Best,
Christine

Zephir said...

/* dark matter filaments resulting from normal ΛCDM structure formation.. has nothing to do with cosmic strings whatsoever, they have nothing to do with wormholes or Einstein-Rosen bridges either. What is shown in the picture is basically matter density. Wormholes are something completely different, they have a non-trivial geometry.. */
Well, and my post just was, they're the same, when you would observe them from 3D perspective. I know perfectly about motivations of your stance, I know their equations are different and this is exactly why I'm saying it just here. If I would know, you realize it, I wouldn't say about it here.

/*You don't need string theory to create cosmic strings per se, thus their existence alone would not be evidence for string theory. What I've tried to explain however is that the cosmic strings in string theory are different.*/

You're completelly right, dark strings arise from application of extradimensions to relativity theory, too. They're not required to be quantized, but when the number of extradimensions will increase, then the quantization emerges as their intrinsic property.

There is another insight of string theorists, the multiverses are composed of slices of Universe with hyperdimensional geometry, which is actually quite right. They just didn't realize, the microscopic and macroscopic worlds described with quantum mechanics or relativity are such multiverses already. The seemimgly quite different worlds described with LQG and string theorists are such hyperdimensional slices, too.

You know, I'm not any particular friend of extra-dimensions and/or string theory - but I'm not blind as well. Actually we can describe the same hypergeometry with nested dynamic triangulation of space-time without introduction of any extradimensions - it's just dual view to the same stuff. For example, we can describe rotation of electrons within atoms within molecules withing planets withing gallaxies in just plain 3D space with complex equations - but we can consider them as a hyperdimensional artifacts from their reference frame, too. The principle of extradimensions is, the motion of objects inside of them remains independent to motion in another dimensions - and this is exactly of what these electrons are doing. Just the projection of simple motion in high number of dimensions to low dimensions appear complex - actually we are talking about insights of holographic theory here, too. Try to imagine the projection of shadow of the rod regularly rotating in 3D to the 2D plane - the shadow of rod will appear shorter in average and it will move irregularly (fuzzy) because of lost of information.

OK, I'll stop to interfere your discussion by now - it's evident, there is really lot of things, which you're expected to swallow right now.

Phil Warnell said...

Hi Bee,

Thanks I have that point, yet what I was interested in being if some observation in the future rules out cosmic strings altogether as being real phenomena what would this suggest respective of the new proposals or more importantly the established theories. To put it another way does quantum field theory mandate that such phenomena should exist, given the early universe being hot and having low entropy?

Best,

Phil

Zephir said...

Can Primordial Magnetic Fields Seeded by Electroweak Strings Cause an Alignment of Quasar Axes on Cosmological Scales? Phys. Rev. Lett. 105, 161301 (2010)
DOI:10.1103/PhysRevLett.105.161301

Steven Colyer said...

Hey, Zephir,
Does Primordial Reality Causated by God Lead to Filament-Void Structure Based on Geometry Times Four With Pi Thrown In Somewhere For Kicks?
http://johncarlosbaez.wordpress.com/2010/10/11/geometry-puzzle/

Bee said...

Hi Stefan, Christine,

Humm, I think I understood Christine's question differently. So then, maybe let me add my own question. Consider you had a 2-dimensional defect created by the appropriate symmetry breaking. What would happen to it when the universe expands? Best,

B.

Bee said...

Hi Phil,

As I wrote in an earlier post, it is rarely the case that one rules out an hypothesis. You constrain it, till it becomes implausible or simply uninteresting. Same with cosmic strings. Predictions depend on some parameters. These parameters are constrained by present day experiments. Better experiments will constrain them better. At some point the word "cosmic string" will become a historical anecdote like, say, the aether. Best,

B.

Bee said...

Zephir:

"Well, and my post just was, they're the same, when you would observe them from 3D perspective. "

I'll try it once again: They are not the same. A dark matter filament is not a cosmic string is not a wormhole. Look up the literature. To begin with, a dark matter filament is many orders of magnitude larger than a cosmic string, it's composed of (guess) dark matter, and a wormhole is a topological feature of the background manifold. It doesn't matter if you want to bring up your "3D perspective" or whatever, that's, excuse me for being blunt, just blahblah.

"it's evident, there is really lot of things, which you're expected to swallow right now"

I'd recommend you go swallow some introductionary texts to general relativity and cosmology. But then, I've told you that repeatedly without having had any success.

"OK, I'll stop to interfere your discussion by now"

Thanks, I appreciate that. Bye then,

B.

Bee said...

Hi Steven,

We also have experimental confirmation for the weak gauge bosons, as well as the muon and tau. I don't know what you want to "start," but please let me remind you that this blog is not the place to discuss your own theories. We're talking here about cosmic strings, and I'd appreciate if you stick with the topic. Best,

B.

Phil Warnell said...

Hi Bee,

Thanks, yet once again I already understand your point that physics not generally being able to emphatically rule something out, only decrease or increase its likelihood of existing or being true. I also appreciate that I shouldn’t consider you as my own personal resource. What I’m trying to understand is if the cosmic string hypothesis is constrained to the point that it is considered like the aether, as for instance if the Higgs is not detected with the LHC, would this suggest the need for new physics or is quantum field theory and/or the standard model not dependent upon its existence to remain consistent. The same query of course would apply to the new proposed theories as they in the main don’t attempt to falsify either, simply to extend their range of explanation or have them become more complete.

I apologize if you think I’m being pesky, as really all I’m asking is for you to address what it is I’m curious about.

Best,

Phil

Bee said...

Hi Phil,

No, it's not (yet) constrained to the point where it becomes implausible, thus the interest in the topic. Best,

B.

Phil Warnell said...

Hi Bee,

So I take it that quantum field theory and/or the standard model not being dependent upon its existence to remain generally consistent. With that being the case I find this has the whole thing become less important from my point of view, as it would be nice to have something have it known if things in general are on the right track or rather somewhere having taken a wrong turn in the road. Oh well I guess I’ll just have to wait for what the LHC turns up, as to have the Higgs fortify the standard model or have it become like the aether and thus force the current position to be re-examined. Damn, it was so much easier when all one had to do was to drop a large and small ball off a poorly constructed tower to have things resolved:-)

Best,

Phil

Bee said...

Hi Phil,

The point is that cosmic strings are formed in the very early universe and thus carry information about what was going on back then. That's why they're interesting per se. If they're super-strings, they would in addition be phenomenology of physics beyond the standard model. In contrast to the aether, the standard model of particle physics is an already well-confirmed theory. It won't become redundant if we find something more fundamental, it might however take the place of just being a limit (which it is generally thought to be anyway). Best,

B.

Phil Warnell said...

Hi Bee,

”In contrast to the aether, the standard model of particle physics is an already well-confirmed theory.

To have what you mean become perfectly clear, do you similarly hold the opinion that if the Higgs is not found that the standard model remains consistent enough to be considered as not needing major reform or even perhaps complete revision?

Best,

Phil

Bee said...

Hi Phil,

"do you similarly hold the opinion that if the Higgs is not found that the standard model remains consistent enough to be considered as not needing major reform or even perhaps complete revision? "

Of course! The standard model is, as a matter of fact, a theory that has proven to describe observation remarkably well. We know it doesn't need "major reform." As I said, it might turn out however that the standard model is only working so well in some limit.

Though, to be careful, the answer to your question is to some extend a matter of semantics. That's because some people do consider the Higgs part of the standard model already. For what I'm concerned, the Higgs is unconfirmed and thus beyond the standard model. Best,

B.

Phil Warnell said...

Hi Bee,

” For what I'm concerned, the Higgs is unconfirmed and thus beyond the standard model.”

I’m sorry Bee yet I find your position rather than being a matter of semantics more one verging on politics. From my point of view the standard model absent of the Higgs leaves it incapable to have an explanation for mass being one consistent within its own framework and thus renders it incomplete.

Best,

Phil

Bee said...

Hi Phil,

If you don't have the Higgs, the masses in the standard model are just parameters. That model is for all practical purposes perfectly fine, is constantly being used, and, as I said, an extremely well confirmed theory. That Phil doesn't like it not having an explanation for the masses doesn't change anything about the model working well. That has nothing to do with politics, the standard model as it is and has been used for decades won't be in for a "major reform," no matter what the LHC will find. What may be in for a reform is the common view on how masses are generated, and possibly we find additional, very massive, particles that have to be added, but that's, as I said, beyond the standard model. Best,

B.

Plato said...

As with Seth Lloyd's illumination, there is information that is not lost?

Much to the consternation that such constraints will make less talk about such topological discussion, it is embedded now that such movements have progressive features that will forever remain in the ideas of what manifests from a ball rolling down a hill, or a pencil falling this way or that, that in the valleys "genus figures" will be progressive features of "new matters of interest?"

Not to forget to mention a progressive feature of the ideas of Navier\Stokes discriminant/application of particularization that manifests from such "smooth expressions of continuity?:)" QGP correlation that helps to define the ideas of what matters come forth in the universe, as we will see in the back drops of our measures whether it be ICEcube or SNO?

That's my opinion of course, as to how we have moved back to the ideas of "phase transitions in the early universe" knowing full well that our views have been pushed back as well to the microseconds.

So you see, while looking at the constraints, there is some evidence of things that still go forward in context of looking at the cosmological expression of this universe?

The excursion is an inductive/deductive relation with the observer and the world one lives in, as to the idea of observing the box and being "outside of that universe?" "The box" is a self evident state of existence, that expresses the toposense of valuations once consumed move toward descriptions beyond the standard model?

Cosmology, does not like to operate "outside that box?:)" Veneziano, Steinhardt and Turok did?:)

Best,

Plato said...

G -> H -> ... -> SU(3) x SU(2) x U(1) -> SU(3) x U(1).

Here, each arrow represents a symmetry breaking phase transition where matter changes form and the groups - G, H, SU(3), etc. - represent the different types of matter, specifically the symmetries that the matter exhibits and they are associated with the different fundamental forces of nature. These fundamental forces are the following:Phase Transitions in the Early Universe

Each phase, is a accumulative example "of the totality of the universe" in it's expression?:)

Understand then "the place" these schematics show of this expression

Best,

Plato said...

Physics at this high energy scale describes the universe as it existed during the first moments of the Big Bang. These high energy scales are completely beyond the range which can be created in the particle accelerators we currently have (or will have in the foreseeable future.) Most of the physical theories that we use to understand the universe that we live in also break down at the Planck scale. However, string theory shows unique promise in being able to describe the physics of the Planck scale and the Big Bang.The goal of string theory is to explain the "?" in the above diagram.

So you see where such "unification of forces" help to direct our views to a time in the universe?

Can we understand such a time with theoretical excursions of the mathematics in order to understand that such expressions of the particulates "have something inherent" through manifestation before such examinations can take place on those backdrop of measures?

Why go there?:)

Best,

Robert L. Oldershaw said...

Two comments:

(1) Regarding the assertions: "The point is that cosmic strings are formed in the very early universe and thus carry information about what was going on back then. That's why they're interesting per se."

Wouldn't a scientist say: "...might have formed...might carry information...might be interesting?" Or qualify the statement by starting with: "If cosmic strings exist"?

Note: I emphatically do not except the "it's implied" or the "it's too cumbersome" arguments. There's the slipery slope, my friends.

(2) Regarding: "the standard model of particle physics is an already well-confirmed theory. It won't become redundant if we find something more fundamental..."

Sigh, the Ptolemaic model and the absolute Newtonian paradigm were "well-confirmed" theories before new paradigms came along and radically changed our thinking.

Why do humans have this nasty habit of thinking that the current paradigms are nearly perfect and permanent, when history teaches us that they are approximations that will probably be replaced by new paradigms that renders their worldview obsolete?

Back to science, anyone?

Bee said...

Hi Robert:

(1) My post was very clear on this matter, and I do not have the impression Phil had any problems with understanding that. If you have a problem, please be assured my comment was not addressed to you.

(2) If you still had use to apply them in a limit where they work to the precision that they achieve, you could use them. You're not really saying the Ptolemaic model was equally well-confirmed as the standard model is today, or did you? Because that's what I understood.

"Why do humans have this nasty habit of thinking that the current paradigms are nearly perfect and permanent, when history teaches us that they are approximations that will probably be replaced by new paradigms that renders their worldview obsolete?"

Why does Robert have the nasty habit of willfully misrepresenting my explanations and putting words in my mouth I never used, and would never use? What I have said is that the standard model is an excellent and well-confirmed theory in the limit that we have tested it. It will continue to do so, even if we find out (as most people expect anyway) that it is only a limit of some more fundamental theory. That does not exclude a paradigm shift telling us exactly how that limit comes along and what's the more fundamental picture. What's your difficulty in understanding this simple point? Best,

B.

Zephir said...

/*..If you have a problem, please be assured my comment was not addressed to you.*/

I've problem with such approach, too. The statements of scientists should be independent to target, Bee. If Robert says, no conclusive evidence of cosmic strings has been given, it simply means, you cannot present them as a fact. There is too many steady-state universe models for some bold claims about strings in "early universe".

Robert L. Oldershaw said...

Well, not to roil already troubled waters, but here is a simple question for you.

Can you imagine a paradigm change occuring within the next 30 years wherein QCD looks in retrospect as ad hoc and misguided as the Ptolemaic model of the "world" did in about 1750?

Or is such a scenario unthinkable?

Bear in mind when forming your answer that the Ptolemaic paradigm did a rather good job of model-building. It retrodicted much of what was known, it could be used to predict eclipses, had strong support from written sources, and was widely accepted by the majority of the intelligensia as the "only game in town" for the correct model of the known "world".

I look forward to your objective and well-reasoned answer.

Bee said...

Zephir:

My post tells the status very clearly. If somebody draws information from comment #37 or whatever of a blogpost he didn't read to begin with, I can't help them. Best,

B.

Bee said...

Robert,

In 30 years, QCD will still be a well-working model that describes inelastic scattering in the energy range from, say 10GeV to 10TeV, to excellent precision. I would hope though that in 3 decades from now we have a better understanding of space-time and matter and know a more complete theory that it is a limit of. Best,

B.

Phil Warnell said...
This comment has been removed by the author.
Phil Warnell said...

Hi Bee,

First let me apologize for apparently given cause (rather than reason) for the axe grinders to chime in, as I can assure you I have no axe to grind or do I intend on ever fashioning one. What I am more curious about, as to be concerned with, being what I would call the more fundamental questions, with those pertaining to the ontological premise(s) of current theory(s), in relation to the particular aspect of phenomena they seem to suggest having need to be present.

In truth also I wouldn’t say I’ve come to be convinced of any particular view, although admittedly find one more appealing than the other; not very scientific I would admit, yet I’ve have never claimed as to being a scientist. More specifically, in respect to things such as cosmic strings and the Higgs, I find them both to be consequential extensions of a particular ontological perspective with which I have some difficulty and thus being curious in the end if they will in fact survive, as to be able to reinforce this view or rather have the opposite to be demonstrated.

So when I suggested your position verged on being political, it was in this regard I considered it as being so; rather than to suggest the standard model not being a successful theory within its currently testable limits.

Best,

Phil

Bee said...

Hi Phil,

Well, I wouldn't say I've come to be convinced of either cosmic strings or some particular proposal for quantum gravity or physics beyond the standard model. But my convictions or absence thereof are somewhat besides the point. What I do believe is that if we keep looking and we keep trying, sooner or later we'll find a hint to the underlying theory. And who knows, maybe it's cosmic strings, or maybe it's in the foundations of quantum mechanics. Time will tell. There's plenty of approaches which attempt to throw out whatever feature of the standard model possibly may be altered, maybe one of them will lead the way. Whatever that new approach looks like however, it will have to reproduce the standard model in the limit that we've tested it, that's all I'm saying. Best,

B.

Phil Warnell said...

Hi Bee,

Not that my opinion on such matters should count for much, yet I would say in essence this clarification of your position coincides with what I would agree as being a truly scientific perspective. That is also to say that I find some practitioners of your discipline not to see things as such, yet rather it be more important who be science’s winners and losers, when in the end increased understanding to be the goal, rather than who or who isn’t proven as being right. My disappoint lies with also finding this consistent with society as a whole, with the majority more concerned with righteousness then the search and promotion of increased understanding.

“ It is open to every man to choose the direction of his striving: and also every man may draw from Lessing’s fine saying, that the search for truth is more precious than its possession. “

-Albert Einstein

Best,

Phil

Bee said...

Hi Phil,

Nice quote, I hadn't know it. Unfortunately, there seem to be many people who cease to search early because they have found truthiness ;-) Best,

B.

Steven Colyer said...

Space.com has an article about the recent work of Robert Poltis at U. Buffalo, here. Mike Lucibella, in the article's conclusion, does a nice science journalist's job of bringing in objective criticism:

Jon Urrestilla of the University of the Basque Country in Biscay, Spain, doesn't want to jump to conclusions too quickly. He said that Poltis' research is exciting because his team is making testable predictions.

"It is still early to say that this work has discovered evidence for cosmic strings. It is promising, the science is sound, but one should be careful. There are assumptions made that need be checked," Urrestilla said, "But it is yet another piece to the puzzle, and the more predictions we can make from the same basic science into presumably independent effects, the closer we will be to detecting whether strings really were there."

Tanmay Vachaspati from Arizona State University in Tempe, a leading expert on cosmic strings, said he thought that the observation of lined-up quasars was puzzling, but he was skeptical it was caused by cosmic strings. He said that had the strings formed nanoseconds after the Big Bang, they probably would have decayed so quickly that their magnetic effect wouldn't last until today.

"I don't see them staying around until today to provide observational signals," Vachaspati said.

Plato said...

For sure, one may call it cosmic string and think society/scientist has this perspective found in trustworthiness about it as "all that," as being in opposition too, another view of equal too "in concreteness," but truthfully, it's how it encompasses a look at the cosmos that one might wonder about the cosmos in it's own nature.

"A bird view or a frog view?"

Inside/outside and I've change the terminology a bit to direct the focus toward?

If one finds it in them self and is trying to explain it, the conundrum is not only about where it begins in the universe, but of where it begins in self too.:)

One might call it is mathematical map/diagram in it's abstractness, but around it, is a whole universe.

So the "toposense" with the internal is involved with the cosmos as well you see:)

The parameters of one's thinking can stop with the froggy:)

Best,

Plato said...

A Myth concerning time, can encompass some truth about the "froggy view?":)

Bashing Branes by Gabriele Veneziano


The pre–big bang and ekpyrotic scenarios share some common features. Both begin with a large, cold, nearly empty universe, and both share the difficult (and unresolved) problem of making the transition between the pre- and the post-bang phase. Mathematically, the main difference between the scenarios is the behavior of the dilaton field. In the pre–big bang, the dilaton begins with a low value--so that the forces of nature are weak--and steadily gains strength. The opposite is true for the ekpyrotic scenario, in which the collision occurs when forces are at their weakest.

The developers of the ekpyrotic theory initially hoped that the weakness of the forces would allow the bounce to be analyzed more easily, but they were still confronted with a difficult high-curvature situation, so the jury is out on whether the scenario truly avoids a singularity. Also, the ekpyrotic scenario must entail very special conditions to solve the usual cosmological puzzles. For instance, the about-to-collide branes must have been almost exactly parallel to one another, or else the collision could not have given rise to a sufficiently homogeneous bang. The cyclic version may be able to take care of this problem, because successive collisions would allow the branes to straighten themselves.


And then coming forward in time, we have today's views.

Plato said...

Hi Steven

To help you with your limited time with the information

Note that this is a cross section through the string, that is, in this movie the string is perpendicular to the screen.

Just trying to help adjust the angle of one's perspective a bit.:)

Best,

Plato said...

Sometimes one forgets how they got to a particular location in thought.

Kaluza-Klein theory is a model which unifies classical gravity and electromagnetism. It was discovered by the mathematician Theodor Kaluza that if general relativity is extended to a five-dimensional spacetime, the equations can be separated out into ordinary four-dimensional gravitation plus an extra set, which is equivalent to Maxwell's equations for the electromagnetic field, plus an extra scalar field known as the "dilaton". Oskar Klein proposed that the fourth spatial dimension is curled up with a very small radius, i.e. that a particle moving a short distance along that axis would return to where it began. The distance a particle can travel before reaching its initial position is said to be the size of the dimension. This, in fact, also gives rise to quantization of charge, as waves directed along a finite axis can only occupy discrete frequencies.

Can you image how excited Einstein might have been?:)Was? I have no evidence.:)

'All this has a very serious undertone,'' Dr. Preskill said. ''If we are ever to understand singularities, we must do so in terms of some yet-to-be-discovered theory of quantum gravity, and that would be a revolution in physics. We're not there yet.' A Bet on a Cosmic Scale, And a Concession, Sort Of By Malcolm W. Browne, New York Times, February 12, 1997

If continuity of expression is ever to be made into the continued nature of particularization, how is it such an expression could have arisen from the QGP? Can it?

The question of a singularity, would have had to be dismissed?

The questions toward the "bird view" would ask that if this had been dismissed then "what dynamics in theory(Navier Stokes)"would have allowed such an expression to take form?

Vorticity, in a viscous liquid?

Best,

Robert L. Oldershaw said...

Dr H: "In 30 years, QCD will still be a well-working model that describes inelastic scattering in the energy range from, say 10GeV to 10TeV, to excellent precision. I would hope though that in 3 decades from now we have a better understanding of space-time and matter and know a more complete theory that it is a limit of."

I think that is a very reasonable answer and one that I can go along with.

The question that has increasingly interested me in the last couple of days is the following.

Are the days of radical paradigm shifts like the one from the Aristotelean/Ptolemaic paradigm to the Democritean/Galilean paradigm a thing of the past?

The corollary is: Are more subtle and sophisticated paradigm shifts like the the one from the absolute Newtonian paradigm to the relative Einsteinian paradigm the only type of paradigm shift we are likely to see in a modern scientific age?

However, I realize that this has drifted off-topic, and so I will not press the issue. But it's something worth thinking about, I think.

Zephir said...

/*..unfortunately, there seem to be many people who cease to search early because they have found truthiness..*/

The seeking for truth must be in balance with finding of truth. Actually I can perceive, the theorists aren't very interested in mutual reconciliation of their theories, until they've their jobs, traveling and conferences and money from public taxis are going.. Actually it's not just my private hypothetical feeling - it's quite real sociological problem, because Prof. Robert Wilson, a former chairman of APS expressed this stance clearly in mafia way:

"Just suppose.. that some smart aleck came up with a simple self-evident, closed theory of everything. I---and so many others---have had a perfectly wonderful life pursuing the will-o'-the-wisp of unification. I have dreamed of my children, their children and their children's children all having this same beautiful experience.

All that would end....APS membership would drop precipitously. Fellow members, could we afford this catastrophe? We must prepare a crisis-management plan for this eventuality, however remote. First we must voice a hearty denial. Then we should ostracize the culprit and hold up for years any publication by the use of our well-practiced referees. Just to be safe, we should put the paper on our Index---I mean in our index--- where it can be lost for centuries...
"

Wilson's memo indicates clearly, the community of physicists is taking Einstein's quote quite seriously and it's willing to prolong their safe life as long, as possible for the money of the rest of society.

And this must simply stop - we aren't paying scientists for research, but for results of research. So if you want to ignore some selfevident connections leading to unification, you can still continue in your useless research for your own money - but it's your ignorance, not ignorance of mine.

Zephir said...

/* Are the days of radical paradigm shifts like the one from the Aristotelean/Ptolemaic paradigm to the Democritean/Galilean paradigm a thing of the past? */

Yes. Actually the problem is quite simple: before one hundred years Sir Oliver Lodge proposed an revolutionary idea, the luminiferous aether is not formed with sparse gas (as such gas cannot mediate the energy of gamma rays anyway), but it may be formed with very dense gas, instead.

This idea was purpotedly ignored by mainstream physics without testing in behalf of abstract and solely formal theories and now the proponents of this idea are called an ignorants instead of people, who are adhering to ignorance of the last century.

The point is, dense aether model can explain most of mainstream theories in quite simple & straightforward way, but it would render all these very educated and clever theorists as an ignorant trolls at the same moment.

So we have a situation by now, based on psychological barrier...

Any solution proposals?

Robert L. Oldershaw said...

"Any solution proposals?"

Maybe we should have a bit less faith in what seems right to us and a bit more respect for what nature teaches us.

Nature has rendered a very clear verdict against the classical static "aether", and an even harsher multiple set of verdicts on any "dense aether".

Zephir said...

/*..Nature has rendered ..an even harsher multiple set of verdicts on any "dense aether"...*/

Nature doesn't render, because it's not a rendering engine - this is just a pseudolanguage of postmodern metaphysical naturalism. Could you provide some evidence for your claim, providing we can substitue "Nature" by some author of scientific article - or you're just living in illusion?

Robert L. Oldershaw said...

I could probably not cite any empirical evidence that would incline you to think that you might be wrong.

Obviously, this is because you cannot be wrong. Right?

Plato said...

Right on Bee:)

The best place to look for quantum gravitational effects is in regions of strong curvature, that would be towards the center of black holes or towards the first moments of the universe. Since black hole interiors are hidden from our observation by the horizon, this leaves the early universe as the best place to look. It is thus not surprising that the bulk of effort has been invested into cosmology, most notably in form of String Cosmology and Loop Quantum Cosmology. Experimental Search for Quantum Gravity - Workshop Summary

Zephir said...

/* Obviously, this is because you cannot be wrong. Right? */

Then we developed theory of everything. Such TOE would be unfalsifiable by its very definition, because it describes everything correctly - so it cannot be a theory in sense of Popper's falsification.

Actually dense aether model can be falsified easily, because we didn't reveal everything already. For example it predicts superluminal speed of gravitational waves or higher generations of particles (which are virtually unlimited). Or infinite Universe extending event horizon and symmetry in Universe expansion (blue shift for radiowaves), etc..

But the main problem is different - nobody of mainstream physicists has ever dealt with Lodge's theory, seriously the less. This theory has been actually never checked, peer-reviewed the less. So you CANNOT have evidence, this theory is actually wrong.

Mainstream science has many tools, how to distinguish and falsify various theories - but it has no tools, how not to ignore or even exclude the relevant ideas prematurely because Popper's methodology of is based on falsification of theories, not on their mutual reconciliation - there is an apparent negative bias. Ignoring of idea is what the ignorance is called - no matter how you're engaged in alternative ideas. But in science such approach is called a healthy skepticism.

Actually the only way, which the mainstream physics is capable of by now is to develop and pile another and another theories. Because scientists are getting more and more specialized, they're losing the ability to merge this increasing pile of theories together. Actually no one is personally motivated in it - the more theories we maintain, the more jobs for theorists we need.

This evolution corresponds the spreading of transverse waves in dispersive environment.

Zephir said...

/* the best place to look for quantum gravitational effects is in regions of strong curvature..*/
..or the regions of very weak curvature, low energy density or at large cosmological distances...

For example the dispersion of photons at large distance is a nifty way, how to detect 1st or even 2nd order phenomena, i.e. not only the violation of Lorentz symmetry, but even the suppression of this violation (...and violation of this suppression of LS violation, etc.)...

But I'd recommend to understand this stuff first and consider its importance for further evolution of human society. We actually have a more rewarding tasks for physicists, then the formal description of nested density fluctuations of particle gas.

Bee said...

Zephir:

Why don't you first read the full text from which Plato quoted a paragraph before you criticize me? Besides that, I recommend you check what CMB polarization is good for, and current measurements esp on the B-modes. Finally, yes, the presence of extra dimensions can, in some cases, be measured with the Casimir effect. You can constrain the ADD scenario with that, people have done it, and in principle you could do it also for the UXD scenario, I wrote a paper on that some years back, but it's outside presently possible precision.

Your comments, Zephir, are mainly ignorant babble full of misconceptions that you never bother to correct, and pretty much everything you say is entirely off-topic. I strongly recommend you stop clogging our comment section now and shut up, as you announced earlier. I'm in a pretty shitty mood and have the cursor very close to the delete button. I hop that was clear. Bye,

B.

Zephir said...

Hi, Bee - I feel sorry for you're feeling wrong. Anyway, I appreciate Your patiency...

Bye, Z.