How does LQG compare to string field theory?

In summary, both loop quantum gravity and string theory propose that everything is made of 1 dimensional loops, or strings. Both are quantum theories, not classic. This means that strings are not moving around space like an every day object, but instead must be defined in terms of a quantum field. So both LQG and string theory are field theories.
  • #36


Originally posted by Ramanujan12
This basically speaks for itself. However much we try to topologically glue things together in string theory there will allways be cracks in the pot ie. there will allways be new fields (porous media) beneath topological structures (potters clay) once the theory dries up; it's mathematical and particle smashing resources). It all depends on what kind of topical glue we use to fix the laws/habits of nature.

I don't understand this, Ramanujan. The fact that some people add crackpottery to good theories doesn't say anything about the theory itself, merely about the person. There are crackpots in the fields of GR and QM, but that doesn't mean there is something wrong with either of these theories.
 
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  • #37
Mentat, indeed. And the best theories come from the most crackpotted minds. The eager young minds of earlly string theory had crack (not that kind) and pot (that's the stuff) in their backgrounds that gave rise to such brilliant ideas as hyperspace and a world made of so many dimensions.
 
  • #38
The fact that people need 'glue' to fix is a bad approach and anti-unity. Start from a single system and work downwards.
 
  • #39
Totally digging the tubing there. If we were going to use glue it have to be glue-gun glue, like these pelastration tubings.



It's great to be back
 
  • #40
Rotational Spectra

Rotational Spectra


A contiuous distribution of energies occur in the translational motion within molecular states. Only specific energies are possible though the Boltzman d law. This Boltzman factor expresses relative P that a quantum state of energy Ei (for short)is at the temperature T. This proves a new factor for temperature change. The factor Gi is the multiplicity of the of the level and is the number of quantum states that have the same energy E (open to change? same energy, depends on E). However more than one rotational state corresponds to J. The degeneracy rises because the component L2 in any direction (of which has angular momentum L) might have any value in multiples or... there are 2J + 1 orientations of L relative to (z) direction and each constituting a separate state at this quantum level. All these states are unmovable states, so the energy level, when its rotational quantum number is say, J, has stats weight of g1=2j+1 unless it is a rigid diotomic one that's EJ=J(J+1 h2/2I. In the boltzman distribution the quantity is n0 and is the rotational state and number of molecules which is nj=0 as a rotational state. Next post, I'll go breifly through the Boltzman factor and the relative polulation.


quibton
 
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  • #41
Hello,

Last time i was here (last year?) I had an idea about Rotational Spectra. I wanted it link in with the Boltzman Law and population theory then ...the eye. I wanted it to relate to the eye, or senses. I was on the way to which the brain, or we, might interpret quantum information from the spectra medium in a given value (at present) being the number of quantum states at energy E as the Boltzman factor says we can identify particles and find their difference. Quantum states having same energy E, was about suggesting the only assumption of one state at one temerature only when all hell would be let loose if we could assume the same value with more than one T. To make a massive jump from the physics to biology (via chemistry) of matter using probablity values allready assumed above, then transfering this knowledge using quantum information for -new- states (assumed outside the known permutations and energy levels allready) I could leap to the neurology side, the brain, whereby I involve the stats used in standard models, to a biologicial specific type. How would I do this? What other levels of T and dependant configurations of such particles and their energy states are there within the axon structure as an example. Within the axons in the optic chiasm of the visual pathway there is a change of signal input. Also could this bring new awareness of particle probability of the de-coherence model when applied to voltage-dependent channels in the presynaptic terminal and ion channeling within brain matter being based on biochemical signal transductions on a general scale. Or to put it all simply, new physics laws in probability (via biochemistry) biophysics were particles then with their molecular states are now creating new interactions in the brain because it is networked differently so there are different probable events and outcomes of those events, introducing new ways of understanding, new ways of thinking about the same theory, ad infinitum.. :rolleyes:


Claire this is my site http://www.cthisspace.com
 
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  • #42
The "marble drop" would speak to this as a probabilistic determination, and mathematical described in recognizing Pascal's triangle? Which path? :smile:

http://www.rand.org/methodology/stat/applets/clt.html

Using marble drops to help visualize these pathways, the proof of Stefan Boltzman in the binomal series, speaks to the chaos generated from considering such probabilties?

https://www.physicsforums.com/archive/t-22217

Long time no see :smile:
 
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  • #43
reminder

in reply to my last post, I'll will continue other thoughts about it when I have more time.

Claire
 
  • #44
quibton said:
in reply to my last post, I'll will continue other thoughts about it when I have more time.

Claire
:biggrin:
Claire ... still the same. Shows up ... disappears ...

Sol we have to wait another 11 months. :smile:
 
  • #45
We seem to have gotten off track here. (Although, it was very interesting to here and see that the members who discuss so much at superstringtheory.com are actually posting here now. I'm a big fan of reading your post.) I find this topic of compare and contrast to be very informative and beneficial, if we could get some more experts to comment. Unfortunately, I am not one of those.

Paden Roder
 
  • #46
hey Claire- nice to see you back on the physics forums!

is there a kurzweilAI.net exodus going on? :biggrin:

"Biology has until now been occupied with taking apart what's already alive and trying to understand, based on that, what life is. But we're finding that we can learn a lot by trying to put life together from scratch, by trying to create our own life, and finding out what problems we run into. Things aren't necessarily as simple — or, perhaps, as complicated — as we thought. Furthermore, the simple change in perspective — from the analysis of "what is" to the synthesis of "what could be" — forces us to think about the universe not as a given but as a much more open set of possibilities. Physics has largely been the science of necessity, uncovering the fundamental laws of nature and what must be true given those laws. Biology, on the other hand, is the science of the possible, investigating processes that are possible, given those fundamental laws, but not necessary. Biology is consequently much harder than physics but also infinitely richer in its potential, not just for understanding life and its history but for understanding the universe and its future. The past belongs to physics, but the future belongs to biology."

Christopher G. Langton


___________________________

/:set\AI transmedia laboratories

http://setai-transmedia.com
 
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  • #47
String theory is fascinating. I want to believe it, but, I just can't get past the background dependent thing. It's like an astonishingly beautiful transvestite.
 
  • #48
Strange comparison above me here:)

I think if we consider the vibrational nature of the string, the harmonic oscillator would have identified the particle when it had reached it ground state?

You put the special glasses on, and the world has a strange and wonderous color to it, that dances and intermingles. In some places, where we see this energy concentration, what kind of gathering is indicative of the nature of these particles?

In the one sense seeing Greg egan's gravity well demonstration you have to wonder. In the one sense probabilistic determinations, defined here, the bell curve , or coins tossed, and how is this landscape moving?

Hyperspace Theory (also called Superstring or Supergravity Theory) begins with Einstein's General Relativity. In 1919, Theodor Kaluza, building upon relativity, made an astounding discovery: light and gravity can be unified and expressed with identical mathematics. This was the beginning of the unification of all physical laws, which is the ultimate goal of physics. There was only one catch. He needed an extra dimension. This fifth dimension, ... continued explanation of the Hyperspace in a simplified form

Hyperspace Theory (also called Superstring or Supergravity Theory) begins with Einstein's General Relativity. In 1919, Theodor Kaluza, building upon relativity, made an astounding discovery: light and gravity can be unified and expressed with identical mathematics. This was the beginning of the unification of all physical laws, which is the ultimate goal of physics. There was only one catch. He needed an extra dimension. This fifth dimension, long recognized as mathematically plausible, had never before been seriously proposed as an actual component of reality. The usefulness of his theory was hard to deny; in five dimensions, there is "enough room" to accomplish the unification of gravity and light, which simply cannot be accomplished when trapped in four dimensional spacetime.


There is an obvious question to be asked at this point. "Where is the fifth dimension?" Kaluza's answer is clever, though suspiciously hard to test. He said that the fifth dimension is too small to see. The fifth dimension is contiguous with our four, but it is curled up, while the others are extended. To understand curled-up dimensions, imagine an ant living on a string (or a Linelander). For all its life, it is only aware of two directions: forward and backward. It lives in a one-dimensional universe. However, if you examine the string very closely, you find that it has a circumference; an extra dimension, curled up and wrapped back onto itself into a circle. If you could stretch this dimension, that is, make the circumference very large, the ant would be living on the two-dimensional surface of a cylinder. But when it's curled up, it effectively is undetectable by the ant, though it may serve as a medium for vibrations or other physical effects.


This Kaluza-Klein Theory (named after Kaluza and one of his students) was a curiosity for a while until people became disenchanted with its bizarre hypotheses and lack of concrete predictions. A common criticism was to ask why, if there could be one extra dimension, why not many? Just how many dimensions did this wacky theory have? For many years, people were content to leave gravity behind and work on examining the nature of subatomic matter via Quantum Mechanics.


Fortunately, in the 1980's, Kaluza-Klein came back with a vengence. The new wave of physicists supporting Hyperspace (higher space) theories had an important element which was missing in the thirties: an exact prediction of the number of dimensions in our universe. By manipulating the formulae of Einstein, Riemann, and the like, they managed to unify all the forces of nature (gravity, the strong and weak nuclear forces, and the electromagnetic force, which includes light) in a single theory. How many dimensions did they need? Ten.

According to Hyperspace Theory, each point in our four-dimensional universe conceals an additional six curled-up dimensions. The image above provides insight on how this might be possible. Here we have a two-dimensional plane viewed at great magnification. At each point in the plane, there are the two curled-up dimensions of a sphere. In our universe, each point contains not a sphere, but a higher-dimensional object: a six-dimensional "Calabi-Yau Manifold." There is a very simple reason why we can't see these manifolds: they are less than 10-33 centimeters across, much smaller than our most powerful microscopes can detect. Nonetheless, the movement of vibrating "strings" through these manifolds may be the source of all of physics.

(Courtesy of Brown University).



Sort of miss Paultrrr as his thinking was quite close to mine and he was developing. Some might have not understood his background? :frown:
 
  • #49
I'll add to this very soon. Why the biology relation? Biology/life is as complex as physics, if not more.

Quibtoness

Claire
 

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