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4
votes
1answer
60 views

What, exactly, is a “delta function p-form” as used in the theory of branes?

In string theory, when dealing with branes, the following happens: We rewrite a worldvolume action $S = \int_{\Sigma_{p+1}} \omega^{(p+1)}$ of a $D_p$-brane as an integral over the whole ...
1
vote
1answer
32 views

Enhanced D-Brane Gauge Symmetry and the string decoupling limit

Consider a system of $N_C$ $Dp$-branes (in Type IIA or Type IIB string theory, depending on whether $p$ is even or odd). In the Les Houches lectures on supersymmetric gauge theories by Berman and ...
2
votes
2answers
219 views

How to find the rank of the matrix $\frac{\partial ^2\mathcal{L}}{\partial \dot{X^\mu} \partial \dot{X^\nu} }$ for the Nambu-Goto string Lagrangian?

In this case $$\mathcal{L}~=~-T\sqrt{-\dot{X^2}X'^2+(\dot{X}\cdot X')^2}.$$ I was reading some books and papers about the constraints in the Nambu-Goto action, and all of them say something like ...
1
vote
0answers
49 views

Flux with or without sources

I want to check whether my understanding about flux is correct. So let me consider a $d$-dimensional spacetime manifold $M$ and a $(p+2)$-form flux (or field strength) $F$. Then there are two ...
3
votes
1answer
52 views

D-branes conserving only half of the supersymmetries

Concerning D-branes as BPS states from T-duality. In D-Branes by Johnson (and other sources) I find the following statement (p.196): "Only the total [supersymmetric] charge of $Q_a+\tilde{Q}_a$ of ...
0
votes
1answer
41 views

Confusion about supergravity multiplet

I have a bit of confusion with the following consideration. Generally, to impose some BPS condition (i.e. to check if some multiplet preserves some SUSY charges) one imposes to zero the SUSY ...
4
votes
1answer
43 views

What kind of fields can couple naturally to a $p$-form gauge fields in a Lagrangian?

Ordinary $U(1)$ gauge fields can naturally couple to classical fields such as spin-$1/2$ fields via the Dirac Lagrangian, or to complex spin-$0$ fields via the obvious covariant derivative coupling, ...
0
votes
1answer
102 views

How can Big Bang happen without time?

I had recently watched a video and he says big bang could have happen by the slow collision rather than a fast collision. But I know that there was no time before the big bang and fast and slow are ...
2
votes
0answers
24 views

Which supersymmetry principles make the axio-dilaton field in F-theory holomorphic?

I am following the lecture notes on F-theory by T. Weigand . On page 7 he states that when considering F-theory as the strong coupling limit of type IIB orientifolds with D-branes, the axio-dilaton ...
8
votes
1answer
267 views

What happens when two D-branes annihilate?

What happens when two D-branes annihilate? Do we get a radiation of strings?
1
vote
1answer
29 views

Type II Superstring and Open String

I would like to trow away some confusion I'm accumulating. Usually when superstrings are introducted (see for example Wikipedia) one says: Type I is a theory of open and closed strings, while Type ...
0
votes
1answer
44 views

Membrane Theory

I'm not a physicist or educated mathematician, so please excuse me if my question is scientifically rudimentary. It concerns Membrane Theory. If all open strings are attached to the surface of the D ...
3
votes
1answer
62 views

What makes the strings (or $p$-branes) that occur in string theory vibrate?

A normal spring (for example in my ballpoint) is made of particles that interact with each other wich makes the string vibrate with a frequency that depends on the material (the particles). Now a ...
3
votes
0answers
71 views

Does Type IIB string theory feature D(-1) and D9 branes?

I'm slightly confused as to how one deduces the D-brane content of a string theory by studying the p-form fields in the effective field theory. In type IIB supergravity one has: The Kalb-Ramond ...
0
votes
0answers
25 views

D4 branes ending on NS5 branes (Witten's construction): query about harmonic functions

This query stems from Witten's paper, ''Solutions of Four-Dimensional Field Theories via M Theory'' (hep-th/9703166). Specifically, consider Type IIA string theory, and suppose one has a stack of NS5 ...
5
votes
1answer
202 views

Mass of a superstring between two branes?

A open bosonic string between two parallel branes seems to obey formulae such as $M^2 = \big((n + {\theta_i - \theta_j \over 2 \pi}) {R' \over \alpha'}\big)^2 + {N-1 \over \alpha'} $ So that the ...
1
vote
0answers
30 views

Superstring mass between 2 D-branes

The mass of a superstring between 2 parallel D-branes of dimension $p$ and $q$ is $$m^2=(N−a)+(y/2π)^2$$ But what is the value of the normal ordering constant $a$?
4
votes
0answers
55 views

Higgs mechanism on a brane- application to a 2d superconductor

In usual three-dimensional superconductors the would-be Goldstone mode is eaten up by the electromagnetic gauge field via the standard Higgs mechanism. I am thinking now about a problem of a ...
2
votes
0answers
41 views

Could a 3+1 space be embedded in a 4+1 space and retain its 3+1 characteristics? [closed]

I'm confused because I can conceptualize this embedding scenario in two seemingly incompatible ways. Which of the following scenarios are possible?: 1) 4+1 space automatically enforces 4 dimensions ...
0
votes
0answers
15 views

C.o.m. position and total momentum of open DD string

I'm trying to calculate c.o.m. position $q_\text{DD}^\mu$ and total momentum $p_\text{DD}^\mu$ of the open string with Dirichlet boudnary conditions on both ends. Something is going very wrong though. ...
1
vote
1answer
41 views

Non-perturbative Brane effects

In Johnson's Book about D-branes he gets the Tension of a D brane: $$\tau_p = \frac{\sqrt{\pi}}{16 \kappa_0 g_s}(4\pi^2\alpha')^{(11-p)/2}$$ By performing a string amplitude calculation and ...
2
votes
0answers
22 views

Rotating Branes and AdS/CFT

Do we have an extension of the AdS/CFT correspondence for rotating branes? Are the rotating branes, the supergravity analog of the Kerr Black Holes in General Relativity? What are the most successful ...
9
votes
2answers
339 views

Why should the modes of the linearized metric perturbation be “wavefunctions” of gravitons (in the Randall-Sundrum model)?

In "An Alternative to Compactification" by Randall and Sundrum, they discuss the localization of "graviton modes" around the Planck brane in the Randall-Sundrum model where we have a compact fifth ...
1
vote
0answers
46 views

Bulk action - Can a brane velocity be defined?

a) If a brane action in a bulk is defined, in that case, that a brane is modelwise moving through a bulk, how is this ratio defined? Is this a regular "velocity" in that meaning, that space is being ...
0
votes
0answers
36 views

What is known about the physics of Planckbrane (another brane) in Randall–Sundrum model?

Randall–Sundrum model imagines that our universe is a five-dimensional anti-de Sitter space and the elementary particles except for the graviton are localized on a (3 + 1)-dimensional brane or branes. ...
2
votes
0answers
40 views

What are the difference between a black holes and a black branes? [closed]

I want to know the fundamental difference between a black hole and a black brane? What is the planar limit?
4
votes
0answers
46 views

Brane interactions?

In particle physics, in QFT's, interactions come from the interaction piece in the Lagrangian (action). In string theory, waiting for a complete formulation of SFT, we have to add "by hand" ...
3
votes
1answer
93 views

What is the relationship between a brane, a manifold, and a space?

I've read many ways to define manifold; one way is to define it as a type of mathematical space (a type of topological space to be exact). All of the definitions that I've seen for brane, on the ...
0
votes
1answer
89 views

In M theory, what size are the branes/D branes?

In string theory strings are around Planck length, but how big are the D branes in M theory? Can we see them with the LHC?
2
votes
1answer
168 views

Is M-Theory and 11D Supergravity the same thing?

Is M-Theory and 11D Supergravity the same thing? Reading Hawking, he uses 11D Supergravity and M-Theory interchangeably. ...
2
votes
1answer
133 views

What exactly is a fundamental string as opposed to a D-string?

What exactly is a "fundamental string" in string theory? For bosonic string theory we have the bosonic string inside a 26-dimensional target space. Introducing supersymmetry, we have the ...
1
vote
1answer
83 views

What's between the branes?

So I'm doing my best to explain M Theory to some friends... Mind you, I'm no expert... When we finally got past the obstacle of more than three dimensions... which can be difficult for folks who ...
1
vote
1answer
56 views

What would happen if two branes collided and stuck together?

There is a theory that the universe began when two "branes" bumped each other, creating the energy that sparked the beginning of our universe. What if instead of separating, they actually stuck, ...
0
votes
0answers
39 views

Galileons and the brane origins of their Galilean invariance

I've been reading through a paper on Galileons by K. Hinterbichler et al. in which they discuss the brane origin of their Galilean invariance (starting on page 9) http://arxiv.org/abs/1008.1305 The ...
0
votes
0answers
61 views

DBI action with Weyl Invariance

The DBI action, given by $S_{Dp}=-T_p\int d^{p+1}\xi e^{-\phi(\xi)}\sqrt{-\textrm{det}\left(G_{ab}(\xi)+B_{ab}(\xi)+2\pi{\alpha}'F_{ab}(\xi)\right)}$ is diff and Poincaré invariant. I want to ...
1
vote
0answers
144 views

Sources that explain strings between two branes, where one brane ends on the other

I can't seem to find a source that explains what happens when there are strings between one brane and another brane, where one brane ends on the other brane. For example, consider a D3-brane ending on ...
0
votes
1answer
61 views

In M-theory, are strings created by membranes?

In M-theory there are 2- and 5-branes, but where are the one-dimensional strings which are responsible for all the particles? Can 5-branes turn into 1-dimensional strings due to compactification?
0
votes
1answer
45 views

In M theory, can a fundamental open string attach to a M5 brane?

I only saw a couple of pages online that showed this so i guess I'll ask on here, can fundamental open 1 string end on an M5 brane?
2
votes
1answer
138 views

In M Theory, what does the M5 brane look like?

In M theory, the fundamental 1 strings are made out of the compactification of an M2 brane. In String Theory: Volume 2, Superstring Theory and Beyond By Joseph Polchinski Pg. 204 He states that ...
4
votes
0answers
56 views

Concerning topology of BPS states of the M5-brane

My question is about the M5-brane in M-theory. I would like to know whether the BPS states of the M5-brane worldvolume theory (especially the 1/2 BPS and 1/4 BPS ones) are independent of the topology ...
0
votes
1answer
96 views

M-theory and Mathematics [closed]

If the framework of M-theory is the right path for a unification of gravity with quantum mechanics, is it obligatory to believe that, at a certain level, reality is not just easily describable by ...
1
vote
0answers
66 views

Fayet-Iliopolous Parameters from Separation of NS5-branes in $(x_{7}, x_{8}, x_{9})$: An ambiguity as to which gauge group the FI parameter belongs

hep-th/9611230v3, page 12 explains how, for a configuration of D3s along $(x_{1}, x_{2}, x_{6})$, and NS5's along $(x_{1}, x_{2}, x_{3}, x_{4}, x_{5})$, the Fayet-Iliopolous D-term coefficient $\zeta$ ...
4
votes
0answers
82 views

Connection between the M5 brane and (2, 0) superconformal field theory

I have read that the worldvolume theory of the M5 brane is a $(2, 0)$ superconformal field theory (SCFT). But I have also learnt from talks that the $(2, 0)$ theory lacks a Lagrangian description. ...
3
votes
0answers
44 views

Type I string theory on $K3 \times \mathbb T^2/\mathbb Z_2$ and the K3 orbifold limit

Consider Type IIB string theory with 4 O7-planes and 32 D7-branes on $K3 \times \mathbb T^2/\mathbb Z_2$. The K3 induces D3-charge on their world-volumes which can be cancelled by the introduction of ...
1
vote
0answers
37 views

D-brane tension of type I D9-branes after T-duality

Type I contains branes with a brane tension which is $\frac{1}{\sqrt 2}$ times that of type II branes. The reason is that, e.g., in the computation of the D9-D9 amplitude the open string is ...
3
votes
1answer
434 views

Creation of a miniature universe?

I am not referring to the experiment being conducted at Lancaster University involving liquid helium and a magnetic field to build a marble sized representation of the early cosmos. My question is: ...
3
votes
1answer
118 views

D-branes in type II string theory

D-branes, as I currently understand them, are submanifolds of spacetime on which open strings can end with Dirichlet boundary conditions. On the other hand, type II string theory is a theory of ...
-4
votes
1answer
106 views

In string theory, are strings really just one dimensional? [duplicate]

Is it possible that they are 3 dimensional? Or what if they are 10 dimensional? Is it allowed that they are more than just one dimensional?
0
votes
0answers
16 views

What about the massless vector mode in ADD model?

I have a question regarding the so called large extra dimensions model (or ADD due to Arkani-Hamed, Dimopoulos and Dvali). It is a extradimensional model with a 3brane to which SM forces and matter ...
4
votes
1answer
160 views

Closed strings = open ones attached to a D0-brane?

I decided recently (to try) to learn String Theory, however from the beginning some newbie questions came up, which haven't given me a break. For this reason, I decided to ask some of them. I'd prefer ...