Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How Branes Came To Be?

  1. May 25, 2004 #1

    What is a Brane ?

    This is a fairly simple example that I am sure can be expounded upon when given "time and ten dimensions"? :smile:

    Pictures can sometimes paint a thousand words, why can't math paint you:)

    (a) Compactifying a 3-D universe with two space dimensions and one time dimension. This is a simplification of the 5-D space*time considered by Theodor Kaluza and Oskar Klein. (b) The Lorentz symmetry of the large dimension is broken by the compactification and all that remains is 2-D space plus the U(1) symmetry represented by the arrow. (c) On large scales we see only a 2-D universe (one space plus one time dimension) with the "internal" U(1) symmetry of electromagnetism.


    http://www.superstringtheory.com/forum/stringboard/messages25/85.html [Broken]
    Last edited by a moderator: May 1, 2017
  2. jcsd
  3. May 27, 2004 #2
  4. May 27, 2004 #3

    Type I bubbles with thin domain walls can be stabilized by the entrapment of various particle modes whose masses become much smaller inside than outside the bubble

    As soon as I read this I knew what you were thinking.

    For me there is great danger in the metaphorical pictures that one can use, for they have to be consistent with current mathematical constructions?

    So where are we going to find such a model?

    I would ask then, what about the understanding of geometrodynamics here, and the effects of sonoluminence. We have been defining this action in respect of the casimere plates, but have yet to touch upon the dynamics we see having encapsulated all those dimensions with time. Is this a safe paradigmal model apprehension that we can move forward with?

    It is very difficult for me to imagine the boundary walls of the bubble in this sense without knowing that it could contain information from photon accumulation, as in the blackhole.

    Assuming the dynamics here might have revealled galaxies in formation, what action would allowed such centers to create new universes if we did not have this center to transform this energy into new possibilities? New suns to be born?

    Calculating the amount of energy contained in such bubbles, is a interesting feature when you might apply it to the schwarzchild radius as a energy determnation, yet how would you calculate such universes but by the nature and developement in time( 13.7 billion years?) is how much energy?

    So you look at phonon dispersal and translation into bubble morphology(surface tension)(http://superstringtheory.com/forum/extraboard/messages12/587.html [Broken] ), and wonder, okay the bubble size reached these dimensions, so why did it burst? The amount of energy contained was, and immediately such collapse signalled blackhole collapse and interactive abilities, to fission? You see :smile: ?

    See http://wc0.worldcrossing.com/WebX?14@77.zThGbdxA64H.3@.1dde3fed/15 [Broken]

    All the time this bubble world is going on, what is happening outside the bubble? In sonoluminence there is a translation going on with phonon dispersal over the bubbles surface and moved inside?

    ds2 = c2(1-2MG/c2r)dt2 - dr2/(1-2MG/c2r) - r2(dq2+sin2qdf2).

    For me such visualizations had to contain the information of supergrvaity in the early universe, and reducing it to Einsten eqautions of the metric had to reveal this thinking as well. The gravity of the current universe?:)

    I have responded quckly here and will now go through the article.
    Last edited by a moderator: May 1, 2017
  5. May 27, 2004 #4
    Using the cosmological constant what value is Omega in terms of critical density?

    I like to http://www.superstringtheory.com/forum/extraboard/messages10/321.html [Broken] people's imaginations?

    In the one sense, "psychologically," mass thinking can activate "counter proposals" by its very presence? :smile:

    Why not a example here :smile: Peter Woit?

    I hope the "humour" is well taken. If you are going to apply the terms of negative energy, then how pervasive can we intend the order of geometries but to have incorporated into life? Fully grokkkkkkkkkked it:)
    Last edited by a moderator: May 1, 2017
  6. Jun 7, 2004 #5
    Are moduli in stringscape like metrics in general relativity because both determine the shape and size of spaces?
  7. Jun 26, 2004 #6
    Branes via differential forms

    I enjoyed the (indirect) superstringtheory.com approach to p-branes (http://www.superstringtheory.com/basics/basic7a.html). One can work through the Maxwell equations via differential forms, say, in Wheeler et al's Gravitation (with nice pictures of diff. forms), and then extend the process to d dimensions with the p+1 form vector potential. Through a simple co-dimensional argument we find that the sources are p-dimensional objects, the p-branes.

    Of course we can't *see* the structure of the branes through this approach, but the exercise is instructive, nevertheless.
  8. Jun 26, 2004 #7
    with the additional dimension totalling 11 when Witten Unifited the 5 different versions of String Theory into M-theory the extra dimension allowed for single strings to strech to the size of an entire univerese or large creating membranes or branes for short.
  9. Jun 26, 2004 #8
    The standard Model has to arise from the brane? In strings how shall we define the issues of http://wc0.worldcrossing.com/WebX?14@118.qKIvc7nofIf.1@.1ddf4a5f/17 [Broken]?
    Last edited by a moderator: May 1, 2017
  10. Jun 28, 2004 #9
    The question for me is how can these geometric objects (p-branes) come to be in the first place? They all are submanifolds of the background spacetime dimensions, the bulk. But what principle sustains their existence? Why don't they immediately dissipate in all directions at the speed of light and thus evaporate into nothingness?
  11. Jun 28, 2004 #10
    How advanced have we become in the realities of the quantum geoemtry and the relevance ot quantum gravity?

    You must know the GR had to be lead too and geometriclaly defined. statistical analysis, a issue in the Probabilities? So how the heck could any geometry come out of it? :smile: So toy models were developed :smile:

    We can become quite flexible when we adopt these views of theoretcial models for consideration, but they don't mean a hell of a lot, if they can not speak to the quantum nature? Think gamma rays. We reduced the nature of th ecosmos to geoemtricallly define issues of quantum natures, and at the same time revealled our thinking both classically and quantifically?
    Last edited: Jun 28, 2004
  12. Jun 28, 2004 #11
    One can at least understand the emergence of the original manifold - at least that it should exist. We still have yet to understand the necessity of its geometry and number of dimensions. But nothing can be described at all without the use of a manifold of some sort. And of course it would have to start out infinitesimally small and grow at some rate. For instant everything violates the causality of its existence.

    But then the issue arises as to how the particles within the original manifold came to be and what sustains their structure. It would seem that if these substructures are mere distortions of the original spacetime, then the continuity of the original manifold would require that any disturbance of these structures would dissipate in all directions like any other wave through a medium. But that does not happen, so particles are not disturbance of a medium. So I wonder if they are the places where the original spacetime is absent. That would mean that particles form a boundary of spacetime. And as I understand it, boundaries don't dissipate like disturbances.
  13. Jun 28, 2004 #12
    Here's another thought:
    It would certainly seem at least that black holes are places were normal spacetime does not exist, that the event horizon is a boundary of spacetime. Now, how is it possible to combine a geometry different from that of black holes to black holes geometry, and how could that combination of differing geometries be additive like the conservation of mass entering the black hole? This suggests that particle geometry is similar to black hole geometry.
  14. Jun 28, 2004 #13
    Not only that, but it is said black holes evaporate; they become smaller and smaller as they shed more and more particles. I seem to remember that black holes even become the size of a few particles themselves until they shed those last few particles. If so, then this is even more suggestive that black holes share the same geometry as other particles, since you would think that it is even more unlikely that geometry can change between objects of the same order of size.
  15. Jun 28, 2004 #14
    Or maybe this that in the high energy colliders such blackholes already exist? :smile:

    The geometry on a classical level is speaking not only to the cosmo, but to something else as well. Why we have to choose the type of discriptions we want about quantum geometry. LQG or Strings? We know strings will allow contiuity in topological considerations while in disrcete forms thsi is only now being discussed. String have theoretically been there :smile:
  16. Jun 28, 2004 #15
    If we consider quantized geometry of some sort, then do we not have to consider whether those different geometries can add, interfere, interact with each other? How would a 4D spacetime interact/interfere with say a 7D spacetime in a non-arbitrary manner. 1D paths of a path integral are all the same type of object with the same dimensionality; so it is easy to understand how they can be added constructively or destructively in the path integral. But 4D is not even of the same dimensionality as 7D, so how would such differing spaces be added constructively/destructively?

    I suppose a amplitude and phase can be assigned to a differing 2D objects/surfaces that wonder in differing regions and then be integrated to see how they interfere with each other, just as they do with differing paths of a path integral. But if we were going to try to get a 4D object/space to interfere with a 7D object/space, then combinatorics would tell us how many different ways each dimension of the 4D space could interact with each dimension of the 7D space, right? Would every scenario where each dimension of the 4D space is integrated with each dimension of the 7D space have to be considered? Where 2D interacts with 2D, would we have to consider how each dimension interacts with each of the other dimensions? Or is there only one way a 2D object and interfere with a 2D object?

    Isn't this the essential question of M-theory where objects of differing dimensionality interact with each other?
    Last edited: Jun 28, 2004
  17. Jun 28, 2004 #16
    I highlighted your last statement because this is the very question of how any standard model shall arise from the brane? The topological movement has to be smooth. The supersymmetrical brane is smooth from this perspective as well.How would these http://wc0.worldcrossing.com/WebX?14@229.BuTYce3bgPj.0@.1ddf4a5f/17 [Broken]?

    Well from a string perspective they've change the very foundation of our thinking? The questions of background versus non background become very important here, and this is where the grounding factors in my thinking have trouble remaining in defintion, so I needed to understand this(to concretize it). The result, is two ways in which we can percieve the nature of such geometries arising for us in discriptive features of quantum gravity.

    What must be realized is that they are both based on geometrical defintions, one albeit, very different from a continuity point of view to one discrete. :smile:

    After all we do like structures( we have a long history of it ). :smile: The logic that Smolin put forward for us in Three Roads was extremely helpful in helping me to orientate a view, because it was by his example, that such model in comprehension could help us undertand how three roads could now have formed a new math? If Glast in taken into consideration,this is a summation to me of Smolins goal, as well as a introdcution to a new undertanding of quantum computation.

    A certain distilliation had to go on on that might be no different then integrating Venn logic from a quantum perspective into some form of probabilty discription?

    If I put Hopf rings into the image of GHZ entanglement what kind of geometry shall we call this? Imagine buiding such psychological determinations from such logic? :smile: Maybe we can reassign these quantum computers in how we shall view AI possibilties :smile: But this is taking it to far, so back down to earth.
    Last edited by a moderator: May 1, 2017
  18. Jun 28, 2004 #17
    OK, let's try this:
    Could it be that M-theory IS quantum gravity? It is said that String Theory is background dependent and M-theory along with it. But it seems like only a matter of perspective between whether we are trying to quantize gravity by considering a "path" integral of every possible spacetime, or considering the interaction of every kind of dimensional brane? At the differential scale one may be no different than the other. Since all the branes at the beginning are no bigger than the universe as a whole. The interaction of all possible branes would be the interaction of all possible spacetimes, right? So the ultimate M-theory may just be a background independent quantum geometry?
  19. Jul 1, 2004 #18
    Black holes as D-branes

    Let us consider the type II superstring, where we only have closed loops of string. It is possible to have a string connecting two different black holes. When the black holes emit Hawking radiation, becoming smaller and smaller as you say, and finally decaying to their ground state, we are left with two D-branes connected by a string.

    See Witten's "Black holes and quark confinement" (http://www.sns.ias.edu/~witten/papers/CurrentScienceVol81.pdf [Broken])
    Last edited by a moderator: May 1, 2017
  20. Jul 4, 2004 #19
    I suppose that each dimensional type of p-brane is described as embedded in the bulk. But each could just as soon be described in "p" dimensional parameter space. And if every sort of virtual interaction must be considered, then every sort of dimensional interaction must be considered. And spacetime itself become the result of every possible interaction.
  21. Jul 11, 2004 #20
    As I understand it, space is filled with a "quantum foam" where every sort of virtual particle spontaneously pops into existence and then annihilate each other. The higher the energy of those particles, the less time they spend in existence. But wouldn't those virtual particles have to include every dimensional type of brane/particle? And wouldn't such a foam have to include every type of interaction between every dimensional type of brane? Isn't this the same as saying that the quantum foam is space, and space IS the interaction of every dimension? And isn't the interaction of every type of dimension the same as quantum gravity? Thus, it would seem that M-theory is quantum gravity, right? Or has somebody already gone this route?
    Last edited: Jul 11, 2004
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook