Questions tagged [branes]

A (p-)brane is a dynamically evolving physical object that generalizes the notion of a point particle to (p) higher dimensions. A point particle can be viewed as a brane of dimension zero, a string as a brane of dimension one, and a membrane (sheet) as a brane of dimension two. Do not use for particles or strings, however, unless in comparative juxtapositions.

Filter by
Sorted by
Tagged with
3
votes
1answer
131 views

How do parallel branes remain parallel?

In Maldacena paper he writes: We start with type IIB string theory with string coupling g, which will remain fixed. Consider N parallel D3 branes separated by some distances which we denote by r. ...
3
votes
1answer
250 views

Can a D-brane be closed and contractible?

Let's consider for simplicity D-branes in bosonic string theory. I have a very basic question whose answer I couldn't find clearly stated in the few textbooks where I looked for it. Take for ...
3
votes
1answer
2k views

Neumann boundary condition and the open string

In string theory, If an open string obeys the Neumann boundary condition, then in the static gauge, one can show that the end points move at the speed of light. The derivation is straightforward, but ...
3
votes
0answers
48 views

The M2 brane of M theory creates the Type IIA string and D2; the M5 brane creates the D4 and NS5. What are the other objects grouped with the D0?

Type IIA string theory is related to M theory with the 10th spatial dimension compactified on a circle.  The origin of the F1 string, D2 brane, D4 brane and NS5 branes is simple: they come from the M2 ...
3
votes
0answers
61 views

Mass deformations in D-brane systems

It is well known that the worldvolume theory of $N$ coincident D$p$-branes is given by the $U(N)$ Yang-Mills theory in $(p+1)$-dimensions. One important feature of this setup is the possibility of ...
3
votes
0answers
48 views

At what coordinate is the D-brane located in the T dual world?

I have a simple question on the geometrical intuition of D branes. I am currently reading the TASI notes by Polchinski. Say one has a bosonic open string with all Neumann boundary conditions and ...
3
votes
0answers
139 views

T-duality rules between D-branes and E-branes

I am trying to understand the time-like T-duality rules in Type II effective actions, and how they relate D-branes to E-branes. In the case of the metric and dilaton, the Buscher rules are unchanged ...
3
votes
0answers
123 views

What is an NS-2 brane?

This question is about topological string theory and it was also posted in MathOverflow. The existence of a new brane called "an NS-2 brane" is predicted in (the second paragraph in the page ...
3
votes
0answers
140 views

D-brane worldvolume actions: Where are the Fermions?

I am studying D$p$-brane polarization (Myer's effect https://arxiv.org/abs/hep-th/9910053) and brane-flux annihilation (KPV mechanism, https://arxiv.org/abs/hep-th/0112197). There is little to no ...
3
votes
0answers
95 views

Fuzzy sphere of polarized D0 branes, non-abelian worldvolume action regime validity

I am studying Myer's paper "Dielectric Branes" (https://arxiv.org/abs/hep-th/9910053v2), where it is shown that a stack of D0 branes polarizes into a spherical D0-D2 bound state. The stack of $N$ D0 ...
3
votes
1answer
146 views

Chern-Simons action for non-abelian brane worldvolume and Tsetlyn's symmetric trace prescription

I am trying to reproduce the results of the (famous) Myer's paper "Dielectric Branes" https://arxiv.org/abs/hep-th/9910053. I am struggling a bit to obtain the numerical factors in the equations. When ...
3
votes
0answers
156 views

Questions about BPS D-branes

For the purposes of this question, I imagine I want to restrict attention to M-theory compactified on $X \times S^{1}$, Type IIA or IIB compactified on $X$, or the A/B topological sigma models on with ...
3
votes
0answers
147 views

For intersecting branes, are we allowed to compactify on a torus such that one of the branes becomes dense in it? What is the result?

The story of how to get chiral fermions in the low-energy effective theory of a string theory with intersecting branes goes something like this: At the point of intersection of two branes, a direct ...
3
votes
0answers
117 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 ...
3
votes
0answers
75 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 ...
3
votes
0answers
290 views

If D-branes are the same as p-branes, and p-branes open out to "another universe", why is the other universe invisible in D-branes?

Related to my other misguided question, D-branes are equivalent to p-branes. D-branes are described by a sheet in topologically trivial spacetime. p-branes are extremal black branes. They have an ...
3
votes
0answers
951 views

Static gauge choice in string theory

In solving different problems in string theory and also in brane theory, we consider this static gauge choice and I think that's due to the local symmetry (Repara. Inv. (RI) and Weyl) that we have in ...
2
votes
1answer
51 views

$D0$ brane and open string bound state radiating a closed string

I had this quite vague picture in my head of how a bound state of two $D0$ branes and an open string might "radiate" a closed string when the open string forms a cusp. I know the idea is ...
2
votes
1answer
2k views

Branes Collision -> Big Bang

Branes Collision - Big Bang http://img84.imageshack.us/img84/4082/collision.jpg Imagine universe occurred when two parallel branes collided, Momentum of Branes converted to big bang kinetic energy ...
2
votes
2answers
255 views

Physics of D-branes

I was following the question What is a D-brane? and I want to ask further: Does each open string have its own D-brane or pair of branes? Do elementary particles arise from oscillation of strings onto ...
2
votes
1answer
579 views

D-branes wrapping divisors and/or cycles

What is the difference between a divisor and a homology cycle? What is the difference between a D-brane wrapped around a divisor and a D-brane wrapped around a cycle?
2
votes
1answer
87 views

Supergravity 3-form $C$ fields from 2d string worldsheets

In supergravity, there are 3-form fields known as C fields. However, according to string theory, the fundamental degrees of freedoms are from string worldsheets (so at most they are fundamentally 2d). ...
2
votes
2answers
82 views

Detecting space-filling $D$-Branes in string theory

I am currently studying Zweibach's "A First Course in String Theory" CH:9 and I have managed to understand mode expansion in the light-cone gauge, at the classical level. Right before ...
2
votes
1answer
573 views

M branes/D branes are solitons?

I'm really confused. In M theory/String theory, the fundamental objects are M/D branes. However, branes by defintion are just solitons. Solitons are just waves that maintain there shape. So if a ...
2
votes
1answer
371 views

What does it mean the term "probe brane"?

What does it exactly mean the term "probe brane"? People say for example: We put a stack of N branes at some point and then a probe brane ..." How do they appear in AdS/CFT? Can you give me an ...
2
votes
1answer
208 views

D-brane book-keeping and non-abelianity

In Becker's book String Theory and M-Theory in the chapter about T-duality and D-brane (Chapter 6) the following comment is made The Chan–Paton factors associate $N$ degrees of freedom with each of ...
2
votes
1answer
166 views

Constraints on open strings absent at the perturbative level

Studying Disappearance of moduli for condensate of open strings and Negative open string norms after BRST cohomology? gave me a huge huge shock! Suppose we have N completely wrapped Dp-branes over a $...
2
votes
2answers
191 views

Understanding the Israel Junction Conditions

The well known and frequently used Israel Junction conditions are the equivalent of Einstein's field equation on a membrane in the brane-world picture. All the sources have this notation: $K_{ab}^{(i)}...
2
votes
1answer
93 views

Does different "side" of D-branes matter?

The picture of wiki showed some strings attached on D-branes. However, consider those D2 branes in 3 dimensional world. Then D2 branes had two "sides". Case 1. Let a string started at one of ...
2
votes
1answer
78 views

Why is the worldvolume theory a $U(1)$ gauge theory?

So in string theory a Dp-brane can be described by a $(p+1)$ dimensional QFT living in its worldvolume. For a string, this is similar to the description of the string as a twodimensional QFT living ...
2
votes
2answers
94 views

Can we have bubbles of the tenth dimension in our universe?

If the gap between the branes in the Big Bounce theory is the 10th dimension, and branes have wrinkles as they collide, can our universe have 'bubbles' in the 10th dimension? This is in reference to ...
2
votes
1answer
242 views

Understanding string theory branes

I've been looking into string theory, and I understand the $D1$ strings, but I find the concept of branes confusing. Are they just $D2$ strings? Or are they woven constructs made out of many $D1$ ...
2
votes
1answer
127 views

4D spacetime as intersection of multiple D-branes

Brane-world scenarios usually consider 4D spacetime to be a 3-brane or a collection of coincident 3-branes. Is it possible that 4D spacetime is instead an intersection (not coincidence) of multiple ...
2
votes
1answer
235 views

CFT with noncompact target space => no well-defined vacuum state?

In Maldacena & Nunez's paper, on page 6, when they discuss the compactification of Type-IIB on $\textbf{R}^6 \times K3$ (with D3 branes wrapped on $\textbf{R}^{1,1} \times \Sigma$ where $\Sigma$ ...
2
votes
1answer
95 views

Is it possible for there to be a spacetime which shares one of our dimensions?

Imagine two 2D spacetimes, one with $x,y$ axes and the other with $x,z$ axes. They share a dimension in common with the x axis. Is it possible that a spacetime which shares at least one dimension with ...
2
votes
1answer
207 views

A question about Kaluza-Klein mechanism

We know that there is a kind of compactification mechanism named Kaluza-Klein theory which states that the extra dimensions can be compacted dimensions such as $T^n$ or $S^n$ and so on. To make the ...
2
votes
1answer
657 views

Curvature of Weyl-rescaled metric from curvature of original metric

I'm trying to go from the low-energy effective action in the string-frame to the corresponding action in the Einstein frame. The action in the string frame has the form $$S = \frac{1}{(2\pi)^7 l_s^8}\...
2
votes
1answer
145 views

The equivalence of two worlds related by T-duality

T-duality in string theory relates a world containing open and closed strings with a D$p$-brane with a compact dimension with radius $R$ with a dual world with a D$(p-1)$-brane with a radius $R'=\...
2
votes
1answer
474 views

Can the compactified dimensions of M-Theory/String Theory become uncurled?

Is it possible for the curled dimensions described in superstring theories to become uncurled and open up. I have read that the big bang could have been the uncurling over 3 dimensions through ...
2
votes
1answer
97 views

If QFT is a sum over 1-D topologies and String Theory over 2-D topologies, what is the corresponding theory for N-D topologies?

My understanding is that perturbative QFT can essentially be described as a weighted sum over 1-D topologies (ie Feynman graphs), and String theory is essentially the generalization to a sum over 2-D ...
2
votes
1answer
84 views

Area element with worldsheet metric in Polyakov action

I became confused while reading this article for the following reason: For $p=1$ we have strings such that the Nambu-Goto action is proportional to the area of the worldsheet embedded by the maps $X^\...
2
votes
1answer
82 views

Casimir Effect and parallel $D$-Branes

In the well-known setup for the calculation of the Casimir effect, we take 2 perfectly reflecting plates, impose the appropriate boundary conditions on the relevant fields (scalar, vector, etc.) and ...
2
votes
1answer
174 views

Do the fields in string theory only live on the world line of the string?

Say for instance we have a $D0$ brane, and this $D0$ brane is charged under the KK field. Does the strength of the KK field only exist on the worldline of the $D0$ brane? Same goes for strings: do the ...
2
votes
2answers
134 views

Would black holes be present in all dimensions? [closed]

I'm watching a video about string theory, in which the fact that gravity is weaker than the other forces is explained in that gravitons aren't bound to our universe directly, and can flow across ...
2
votes
2answers
125 views

Are D-branes or M-branes described by wave functions? [closed]

I know that point particles and strings are, but what about branes?
2
votes
0answers
48 views

CFTs describing branes

In this paper section 3, the author describes how a $U(N) \;\mathcal{N}=4$ SYM theory can be coupled to 2 boundary 3D CFTs. Then the boundary CFT would describe the low-energy physics of $N$ semi-...
2
votes
0answers
63 views

Deriving einbein action from Polyakov $p$-brane action

In this paper the author derives a "Polyakov style" $p$-brane action which is given by \begin{equation} S_{p}=-\frac{T_{p}}{2} \int d^{p+1} \xi \sqrt{-g}\left(g^{A B} h_{A B}-(p-1)\right) \...
2
votes
1answer
89 views

A-brane boundary conditions

This question concerns the boundary conditions that A-branes solve. Consider the following problem: Suppose that an A-brane wraps a submanifold $Y$ of $X$. Let $\mathcal{L} \rightarrow Y$ be a rank ...
2
votes
1answer
74 views

Chemical potentials for D-brane bound states

This question is about a mathematical subtlety arising in the computation of the partition function of a supersymmetric ensemble of some lower dimensional $D$-branes attached to a stack of higher ...
2
votes
0answers
47 views

Born-Infeld term for $D$-brane low energy effective action

I am trying to reproduce the Born-Infeld term for the $D$-brane action as explained in Szabo's BUSSTEP Lectures and must admit I am utterly confused by some of the steps. This is a long and technical ...