Topic: Brane
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Brane - Wikipedia, the free encyclopedia
Branes are objects in M-theory and its offshoot, brane cosmology.
In M-theory, p-branes (the name is derived from membrane) are objects of spatial dimensionality p (for example, a string is a 1-brane and a flat surface is a 2-brane).
In brane cosmology, the term "brane" is used to refer to objects similar to our four-dimensional universe, which move in a higher-dimensional "bulk".
en.wikipedia.org /wiki/Brane (88 words)
Brane Theory (Site not responding. Last check: 2007-11-06)
Essentially, a brane is a discontinuity in space-time, a boundary where things meet, like the surface of a pond where the water meets the sky.
Brane worlds (like the one we might live in) must by necessity be "3 plus 1" branes — three dimensions of space plus one of time.
But even if brane worlds aren't real, Carroll said, "they will have taught us a useful lesson that we should have known all along, which is that we don't have a clue to what's going on." Polchinski, for one, believes that branes are probably real, even though he isn't sure where the idea will lead.
www.theosophysandiego.org /Featured/branethe.htm (2393 words)
Encyclopedia: Brane cosmology
Brane cosmology is a protoscience motivated by, but not rigorously derived from, superstring theory and M-theory.
In the brane picture, the other three forces (electromagnetism and the weak and strong nuclear forces) are localised on the brane, but gravity has no such constraint and so much of its attractive power "leaks" into the bulk.
The Randall-Sundrum, pre-big bang, ekpyrotic and cyclic scenarios are particular models of brane cosmology which have attracted a considerable amount of attention.
www.nationmaster.com /encyclopedia/Brane-cosmology (828 words)
Brane - Interview with Lisa Randall, Ph.D.
Another is that we live on a second brane, which is the case where we discussed the hierarchy problem.
We generally assume that we live on a brane, but it may not be the brane on which gravity is concentrated.
So gravity is concentrated on one brane, the Planck brane, and we live on a second brane, not precisely on top of the first brane but a little apart.
www.esi-topics.com /brane/interviews/DrLisaRandall.html (1887 words)
Edge: THEORIES OF THE BRANE
Branes allow for an entirely new set of possibilities in the physics of extra dimensions, because particles confined to the brane would look more or less as they would in a three-plus-one-dimension world; they never venture beyond it.
The aforementioned second brane appeared to serve two purposes: It explained the hierarchy problem because of the small probability for the graviton to be there, and it was also responsible for bounding the extra dimension so that at long distances (bigger than the dimension's size) only three dimensions are seen.
Branes don't even all have to be three-plus-one-dimensional; maybe there are other dimensions of branes in addition to those that look like ours and are parallel to ours.
www.edge.org /3rd_culture/randall03/randall03_print.html (4175 words)
Stretching your brane (Site not responding. Last check: 2007-11-06)
Branes reside in the hidden dimensions, known as ``the bulk.'' While matter and light stick to the branes, gravity traverses both branes and bulk.
Many brane scenarios, the Michigan physicists found, are inconsistent with current estimates of the age of the universe and measurements of the amounts of various chemical elements created in the big bang.
Furthermore, it's hard to reconcile certain brane approaches with a constant strength of gravity in the universe today, Dr. Freese said in an e-mail interview.
fnth37.fnal.gov /lykken/dallas.html (2043 words)
In this description the movement of the brane turns out to be exactly described by the standard Friedmann equation in which the size of the universe directly corresponds to the distance of the brane to the center of the fl hole.
The entropy density and temperature of the CFT at the moment that the brane crosses the horizon are calculated in section~4.
At the horizon $V=V_H$ and hence the entropy density on the brane is $s=1/4\mathbf{G}_N$.
www.vic.com /siopsis/papers/01/0102042 (3914 words)
Branes
Branes are defined by the number of dimensions.
The motion of branes in space-time may be described by the simple dynamics of the gauge theories which arise on their space-time world volumes.
Many brane scenarios are inconsistent with current estimates of the age of the universe and measurements of the amounts of various chemical elements created in the big bang.
www.kheper.net /cosmos/quantum_physics/branes.html (848 words)
Brane cosmology -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-11-06)
Brane cosmology is a (Click link for more info and facts about protoscience) protoscience motivated by, but not rigorously derived from, (Click link for more info and facts about superstring theory) superstring theory and (Click link for more info and facts about M-theory) M-theory.
The central idea is that our visible, four-dimensional (Everything that exists anywhere) universe is entirely restricted to a (Click link for more info and facts about brane) brane in a (Click link for more info and facts about higher-dimensional) higher-dimensional space, called the bulk.
The additional (The magnitude of something in a particular direction (especially length or width or height)) dimensions may be (A small cosmetics case with a mirror; to be carried in a woman's purse) compact.
www.absoluteastronomy.com /encyclopedia/b/br/brane_cosmology.htm (312 words)
In String Theory, What Is A Brane? - Bad Astronomy and Universe Today Forum
Branes are a generalization of strings in M-Theory, which is the superset of the different string theories.
Branes aren't universes as such, they are just the elementary components in M-Theory just as strings were before.
In the still rather hypothetical brane cosmology the universe is a 3-brane and everything in it is open ended strings that are stuck to it.
www.bautforum.com /showthread.php?p=346304#post346304 (1196 words)
The search for extra dimensions (November 2000) - Physics World - PhysicsWeb (Site not responding. Last check: 2007-11-06)
This 3-D surface is known as a "brane", a name derived from membrane, the 2-D equivalent.
The electromagnetic, weak and strong forces, trapped within the 3-D brane, are not aware of the extra dimension and so maintain their usual behaviour.
String-theory p-branes are good candidates for brane worlds because they possess gauge symmetries on their "surfaces" and automatically incorporate a quantum theory of gravity, namely string theory.
physicsweb.org /article/world/13/11/9 (2821 words)
When Branes Collide: Science News Online, Sept. 22, 2001 (Site not responding. Last check: 2007-11-06)
That "brane" (blue at left) is known as a boundary brane because it lies at one boundary of the fifth dimension.
Many physicists are studying branes in the hope of linking gravity and the other fundamental forces of nature to the elementary particles that communicate these forces.
Moreover, Linde claims that the branes in the ekpyrotic model are not truly uniform in structure and therefore can't account for the large-scale uniformity of the universe.
www.sciencenews.org /articles/20010922/bob9.asp (2614 words)
Is there a more fundamental theory?
In terms of branes, what we usually call a membrane would be a two-brane, a string is called a one-brane and a point is called a zero-brane.
Roughly speaking, a D brane is a p-brane where the ends of open strings are localized on the brane.
D branes are important in understanding fl holes in string theory, especially in counting the quantum states that lead to fl hole entropy, which was a very big accomplishment for string theory.
superstringtheory.com /basics/basic7.html (677 words)
D-brane (Site not responding. Last check: 2007-11-06)
Intriguingly, there are just as many massless scalars as there are directions perpendicular to the brane; the geometry of the brane arrangement is closely related to the quantum field theory of the particles "living" on it.
In fact, these massless scalars are Goldstone excitations of the brane, corresponding to the different ways the symmetry of empty space can be broken.
If we regard two overlapping branes as distinct objects, then we still have all the sectors we had before, but without the effects due to the brane separations.
www.worldhistory.com /wiki/D/D-brane.htm (1597 words)
Luboš Motl's reference frame: Types and meaning of the branes
The word "brane", created by removing "mem" from a "membrane", is a generalization of a "membrane" that can have an arbitrary number of spatial dimensions.
Moreover, we require that the brane does not destroy any rotational symmetries between the dimensions transverse to the brane, and it also preserves the translational and Lorentz symmetries involving the dimensions along the brane worldvolume which is the subspace of spacetime spanned by time as well as the spatial dimensions of the brane.
The last condition implies that a sheet of paper is not quite a brane because the Lorentz symmetry is spontaneously broken by the sheet of paper: there is a preferred reference frame associated with the atoms of paper.
motls.blogspot.com /2005/01/types-and-meaning-of-branes.html (3825 words)
Brane-Cantenac wines at Berry Bros & Rudd
Brane Cantenac was perceived throughout much of the 70s and 80s as an underperforming property.
Consequently, the wines at Brane Cantenac now show more weight and concentration, although they still possess that haunting bouquet and quintessential elegance that characterise the wines of Margaux.
The impressive and haunting façade of Château Brane- Cantenac lies west of the village of Cantenac in the Margaux appelation.
www.bbr.com /US/db/producer/3511?first_product_F=1&ID=null (622 words)
Brane
Randall is Professor of Physics at Harvard University, where her research is concentrated in the area of particle physics.
Our Special Topics analysis of work in brane theory over the past decade ranks Dr. Duff at #5 among scientists by total citations, with 40 papers cited a total of 1,707 times.
Classical and Quantum Gravity is ranked at #6 among the journals publishing papers on brane theory in the last decade, with 122 papers and a total of 897 cites to its credit.
www.esi-topics.com /brane/interviews/interview-menu.html (495 words)
Brane World versus Kaluza-Klein (Site not responding. Last check: 2007-11-06)
It is important to realise the difference between the brane world and the better known Kaluza-Klein scenario.
In Kaluza-Klein all fields feel the extra dimensions whereas in the brane world, only a subset of the fields (gravity and moduli fields in string theory) feel all the extra dimensions.
Things are very different in the brane world scenario as we can see for the case of the type I string.
fisica.usac.edu.gt /public/curccaf_proc/quevedo1/node17.html (712 words)
Brane Space LLC
BRANE is a powerful web-based Team Collaboration Application for workgroup project management designed for your Microsoft Windows Server.
BRANE brings a new dimension in supporting team collaboration and rigorous project workgroups in a single, yet flexible, environment.
BRANE Work Space is where the collaboration and work take place!
www.branespace.com (254 words)
Not Even Wrong » Blog Archive » What is a Brane? (Site not responding. Last check: 2007-11-06)
He begins by noting that "The term 'brane' has come to mean many things to many people" and one of the difficulties of the subject is that one has to figure out from context what sort of brane someone is talking about.
As usual though, he insists that the full dynamics of the branes in M-theory is completely determined and unique even though he doesn't know what it is in any phenomenolgically realistic background.
In this language the boundary conditions at the branes can be described as a 1d curve in the phase space.
www.math.columbia.edu /~woit/blog/archives/000131.html (1839 words)
Brane world gravity (Site not responding. Last check: 2007-11-06)
A half-day meeting entitled ``Brane-world gravity" was held at Imperial College London on 13th November 2002, under the auspices of the Gravitational Physics Group of the Institute of Physics.
The meeting gave an overview of the state of the art in brane world gravity, in a form accessible to non-experts and the many graduate students present.
John March-Russell began with an overview of the physics of brane worlds, including the latest experimental constraints, from colliders, astrophysics and cosmology.
www.phys.lsu.edu /mog/mog21/node13.html (270 words)
M Theory Visionists - The Importance of Tipping Light Cones
Using the brane scenrios helps to enlighten the relevance of how and what is held to the brane.
The uncertainty relations from quantum mechanics, when interpreted as a physical axiom, prohibit any local and realistic interpretation, because their immediate consequence is a spreading of wave packets that rather runs against the whole construction of a conventional approach based upon relativity.
Strings vibrate in ten dimensions, six of which are tightly coiled in on an unmeasurably small scale and four of which are in conventional space-time.
wc0.worldcrossing.com /WebX?14@142.dGgUbo7NA8W.21@.1dde934e/98 (1389 words)
Chateau Brane-Cantenac (Site not responding. Last check: 2007-11-06)
In 1833 it was purchased by "Baron de Brane", the famed viticulturalist often referred to as "The Napoleon of Wines" who had sold his estate of Chateau Mouton- Rothschild to finance his acquisition.
Chateau Brane Cantenac lies west of the village of Cantenac, relatively inland from the Gironde Esuary on what is known as the "Le Plateau de Brane".
The estate encompasses various plots on the plateau, the largest being located directly in front of the chateau and there are 90 hectares under vine on a deep soil of quarternary Gunzian gravel, at places 10 metres deep.
www.wine-journal.com /branecantenac.html (1117 words)
SPACE.com -- 'Brane-Storm' Challenges Part of Big Bang Theory
The branes in between, while they may contain matter, are not universes, and they do not resemble the brane we inhabit.
The theory of inflation accounts for this by putting all matter in one spot at the beginning, then shooting it outward faster than the speed of light in a period of inflation whereby everything developed under similar rules regardless of where it was headed.
Ovrut said that in modeling a collision of branes, his group found that the result would be a universe that fits neatly with predictions of the Big Bang.
www.space.com /scienceastronomy/astronomy/bigbang_alternative_010413-2.html (653 words)
Brane World Cosmology Comes Down to Earth
There were five 10D supergravity theories and one 11D theory, all of them assuming that the higher spatial dimensions are extremely compact.
But this hyperspace knot unraveled in the 1990s: theorists proposed that higher-dimensional extended objects, known as branes, could be embedded in spaces including five or six large dimensions.
In two dimensions the brane is a sheet, or membrane ("M-brane") and in three dimensions a real world just like ours.
www.sciencewatch.com /july-aug2002/sw_july-aug2002_page6.htm (918 words)
Looking for extra dimensions
Light is made of electromagnetic radiation, and in a braneworld model, the charges and the fields should propagate only on the brane.
There are still Kaluza-Klein modes of oscillation in the extra dimensions, but because they couple through gravity, and gravity is mostly confined to the brane, they are effectively invisible to our world on the brane.
One problem with theoretical models of gravity and particle physics is that before they can make unique testable predictions of new physics, they have to be worked on so that they don't contradict any existing theoretical or experimental knowledge.
superstringtheory.com /experm/exper51.html (989 words)