giuseppe

2005-05-12 07:41:15 UTC

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could anybody tell me something about braneworld?Raw Message

are there any good books or references you could give me?

Thanks

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giuseppe

2005-05-12 07:41:15 UTC

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could anybody tell me something about braneworld?Raw Message

are there any good books or references you could give me?

Thanks

Urs Schreiber

2005-05-12 08:23:55 UTC

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could anybody tell me something about braneworld?

are there any good books or references you could give me?

"brane world" which share some common ingredients but are rather disjoint,

as far as I am aware.

One of them is concerned with making cosmological models where some (our)

universe is modeled as the worldvolume of a p-brane (3-brane in particular)

which itself propagates in a higher-dimensional spacetime.

Reviews of this approach are for instance

Roy Maartens:

Brane-world gravity

http://arxiv.org/abs/gr-qc/0312059

E. Papantonopoulos:

Brane Cosmology

http://arxiv.org/abs/hep-th/0202044

and

David Langlois:

Brane cosmology: an introduction

http://arxiv.org/abs/hep-th/0209261

These brane world models are often (not always) more "string inspired" than

really string theoretic in that all they (often) really take as input from

string theory is the idea that there may be something like branes in the

first place.

I am not an expert on this stuff, but personally I find it interesting that

in these brane models it is rather natural to find realizations of the

inflaton field in terms of tachyonic string modes between brane/anti-brane

pairs or in terms of "radions" or other moduli. See for instance

Burgess, C. P.; Martineau, P.; Quevedo, F.; Rajesh, G.; Zhang, R. -J.:

Brane-Antibrane Inflation in Orbifold and Orientifold Models

http://arxiv.org/abs/hep-th/0111025

The inflaton and the Higgs field are the two famous tachyonic fields that

are postulated by our currently best ("standard") models of cosmology and

particle physics, without having been observed yet.

The other research area often associated with the word "brane world" is that

part of string phenomenology which tries to realize the standard model of

particel physics by studying compactifications of string theory with

intersecting D-branes in the compact dimensions. Since there are open

strings stretching between D-branes and since the low-energy effective field

theory of generated by these depends on the nature of these D-branes, one

can engineer a wide variety of standard-model-like effective field theories

by considering string backgrounds with suitable configurations of

intersecting D-branes.

Reviews for this topic are for instance

Ralph Blumenhagen, Mirjam Cvetic, Paul Langacker, Gary Shiu

Toward Realistic Intersecting D-Brane Models

http://arxiv.org/abs/hep-th/0502005

or

Fernando Marchesano:

Intersecting D-brane Models

http://arxiv.org/abs/hep-th/0307252 .

Here, too, it is interesting how the important tachyon, in this case the

Higgs, is realized in these models. See for instance

D. Cremades, L.E. Ibanez, F. Marchesano

Intersecting Brane Models of Particle Physics and the Higgs Mechanism

http://arxiv.org/abs/hep-th/0203160

Lubos has a while ago reviewed a recent paper on this topic

http://groups.google.de/group/sci.physics.strings/msg/45ffb6f2b0b3f8a6?hl=de

Lubos Motl

2005-05-18 12:17:32 UTC

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could anybody tell me something about braneworld?

are there any good books or references you could give me?

braneworlds. It's Lisa Randall's "Warped Passages" and its British version

will appear on June 1st:

http://www.amazon.co.uk/exec/obidos/ASIN/0713996994/

Lisa Randall is almost definitely a/the world's leader in the branewolds.

The U.S. edition will appear in September.

http://www.amazon.com/exec/obidos/tg/detail/-/0060531088

"Braneworld" is a phrase that describes the models of the real world in

which the usual matter particles and non-gravitational forces are confined

to higher-dimensional generalizations of membranes - these generalizations

are called "branes" - objects that are embedded in a spacetime whose

dimension is even larger - much like a sheet of paper flies in

three-dimensional space. Only gravity "feels" the whole five-dimensional

(or higher-dimensional) spacetime while the other forces only know about

the membrane (brane) only. Surely, if these models are correct, our world

itself is a braneworld, too. ;-)

e***@yahoo.com

2005-05-28 11:08:13 UTC

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Raw Message

could anybody tell me something about braneworld?

are there any good books or references you could give me?

which the usual matter particles and non-gravitational forces are confined

to higher-dimensional generalizations of membranes - these generalizations

are called "branes" - objects that are embedded in a spacetime whose

dimension is even larger - much like a sheet of paper flies in

three-dimensional space. Only gravity "feels" the whole five-dimensional

(or higher-dimensional) spacetime while the other forces only know about

the membrane (brane) only. Surely, if these models are correct, our world

itself is a braneworld, too. ;-)

Thanks to Peter Woit, I am aware that string theory may have problems

with the kaluza-klein approach due to the "landscape" problem -- that

there are more than 10^500 ways to compactifiy the additional 6-7

dimensions beyond the 4 large dimensions as Yau-Calubi manifolds. the

anthropic princple has been invoked suggesting at least one of these is

consistent with our world (the other worlds may exist as part of a

multiverse)

1 -What i wonder is whether the braneworld scenario has fewer landscape

problems, as they do not have to be "compactified" and hence more

"predictive" than the kaluza-klein approach.

2 Also, i am aware the braneworld approach may help explain why gravity

is so weak relative to the other forces (gravitons "leak" to higher

dimensions), but do the kaluza-klein compactification offer a similiar

explanation for the weakness of gravity?

3- is it possible for both to be partially correct, by breaking them

down, perhaps there are 4 large dimesions, 3 large "braneworld" 3

kaluza-klein compactified dimensions?

R.X.

2005-05-28 16:31:43 UTC

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Generically brane world models are dual, ie equivalent to other stringRaw Message

compactifications (sometimes even without branes), and thus won't have

any particular advantage or disadvantage as compared to other

descriptions of the same thing.

What you attribute to Woit is nothing new, and has been known since

decades to people working in the field.

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