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
1
vote
0answers
39 views

Chiral zero modes in type IIB matrix model

I have seen many articles in which the authors consider various modifications of IKKT matrix model (non-perturbative regularization of type IIB string theory) such as (Orbifolds, fuzzy spheres, ...
2
votes
1answer
45 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 ...
1
vote
0answers
36 views

Physical origin of coisotropic branes

The paper "Remarks on A-branes, Mirror Symmetry, and the Fukaya category" develops the possibility of A-model open strings ending on a coisotropic submanifold equipped with a holomorphic ...
10
votes
2answers
153 views

Is there a description of D-branes from the worldsheet CFT perspective?

D-branes are best known as hypersurfaces in spacetime on which open strings with Dirichlet boundary conditions can end. Furthermore, they have several geometric properties associated with them, such ...
3
votes
0answers
53 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 ...
4
votes
2answers
141 views

Action dimensions in string theory

Disclaimer: I'm tagging this as "string theory" because the doubts came to me studying the actions in string theory, but the underlying problem could be about the concept of the action ...
3
votes
0answers
47 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 ...
4
votes
3answers
154 views

Identity of dynamical D$p$-branes

In my String Theory course, we introduced D$p$-branes, and I'm having trouble picturing them as dynamical objects. We analyzed the open and closed bosonic strings, found the EoM, quantized them, and ...
2
votes
2answers
107 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
2answers
65 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 ...
3
votes
1answer
77 views

Are there consistent theories of GR where our Universe is embedded in higher dimensional space?

In GR we have a metric space given by the metric $g^{\mu\nu}(x)$. This allows us to deetermine the curvature $R^{\mu\nu}$ at each point in space-time. This curved 4D manifold is not required to be ...
5
votes
0answers
138 views

$T$-duality in effective gauge theories of a $D(p+1)$-brane

I am considering a $D(p+1)$-brane in a space $\mathbb R^{1,p}\times S_R^1$ where $S_R^1$ is the circle of radius $R$. I am assuming low energies $ER\ll1$, so that only the massless spectrum of the ...
5
votes
0answers
123 views

Transformation of the string coefficient under T-duality

I am trying to study an effective string theory valid in the low energy limit $ER<<1$. The effective action corresponds to a $D(p+1)$-brane in $R^{1,p}\times S^1$ and it is given by $$S_{D(p+1)} ...
2
votes
1answer
73 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 ...
0
votes
2answers
56 views

Rolled-up dimensions vs surfaces in a higher dimensional space

All the accounts of dimensions higher than 4 seem to talk about them being 'rolled up'. Is this different to being confined to a 4D surface that exists in a higher dimensional space?
1
vote
1answer
117 views

Why are these open string oscillation modes identified with spin 1 particles on the brane?

On page 55 of David Tong's String Theory lecture notes, during the discussion of the first excited states of open strings, two classes of states are identified, both of which are massless. The first ...
2
votes
1answer
168 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 ...
1
vote
0answers
35 views

Macroscopic dimension of a brane

I'm reading Witten's Solutions Of Four-Dimensional Field Theories Via M Theory, where it is discussed a configuration of threebranes stretched between fivebranes. My questions are: how can I ...
3
votes
0answers
126 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 ...
1
vote
1answer
54 views

Motion open string

In the introduction book of Zwiebach, he mentions in chapter 6 that the endpoints of an open string move with the speed of light. First, I assume he means in the longitudinal direction. But then, ...
2
votes
1answer
84 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 ...
0
votes
2answers
77 views

Are branes as fundamental as strings or not?

Are D-branes in string theory as fundamental as one-dimensional strings, or are strings more fundamental and multi-dimensional branes are "woven" from one-dimensional strings?
9
votes
1answer
180 views

The action of the Kaluza–Klein reduction (Chapter 4 of “D-branes (Clifford Johnson)”)

In the first part of Section 4, the author gives \begin{equation} S = \frac1{16\pi G^N_{(5)}}\int(-G_{(5)})^{1/2}R^{(5)}d^5x = \frac1{16\pi G^N_{(4)}}\int(-G_{(4)})^{1/2}\Big(R^{(4)} - \frac32\...
11
votes
2answers
338 views

Is it possible to bound a single D0-brane to a D4-brane?

I'm studying the Jafferis solution for twisted $N=4$ Yang-Mills theory in four dimensions from the paper Crystals and intersecting branes. Consider the problem of computing the charges of the allowed ...
2
votes
1answer
71 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 ...
1
vote
0answers
57 views

Show that a system of intersecting $D4$-$D6$ branes is supersymmetric

The paper "Supersymmetric Gauge Theories, Intersecting Branes and Free Fermions" asserts (first paragraph, page 12,section 2.4) that a system of $N$ $D4$-branes intersecting with $k$ $D6$ ...
0
votes
2answers
114 views

What is brane inflation, and can it be eternal?

What is Brane Inflation and how does it describe inflation process? Can it be eternal?
2
votes
0answers
43 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 ...
2
votes
0answers
72 views

$(p,q)$-5 webs from $M$-Theory

The authors of the paper "Webs of (p,q) 5-branes, Five Dimensional Field Theories and Grid Diagrams" consider type $IIB$ superstring theory compactified on a circle $S^{1}$ and claim (in ...
4
votes
0answers
50 views

D-brane, and SUSY charges

The following results summarize the relation between orientifold and D-brane, and SUSY charge $$ \begin{array}{l||c|c|c|c|c|c}\text{orientifold} &\text{O4} & \text{O3} & \text{O2} &\...
0
votes
0answers
22 views

How can a membrane be a solution of 11D supergravity?

What does it mean that an M2 brane is a solution of 11D supergravity? Does this mean that there is some sort of black hole whose singularity is stretched out into a sheet like a membrane? So that the ...
0
votes
1answer
99 views

Why aren't black holes the same as M2 branes?

If there was an M2-brane with the topology of a sphere. Then I can't see why there are not the same thing? They both have the same topology if we consider the black hole event horizon. Both seem to ...
7
votes
4answers
134 views

The nature of the space in which we exist

I'm looking for pointers to give me a better understanding as to what 'space' is. I do not mean the descriptions of what's in 'space' i.e. not interested in descriptions of outer space filled with ...
1
vote
0answers
40 views

Tension and horizon radius of brane (String theory and M-theory by Katrin Becker)

In exercise 12.1 tells the relation between $N_2$, the number of M2-brane, and $r_2$, the horizon radius. The following relation is derived $$-g_{00} = -1 + \frac{16\pi G_{11}N_2T_\text{M2}}{9\...
5
votes
1answer
111 views

D-branes as the atoms of Calabi-Yau crystals

I'm studying the Nishinaka-Yoshida crystal models that encode the generating function of $D4$-$D2$-$D0$ BPS bound states on a Calabi-Yau divisor. The case of conifold at its singular point is ...
3
votes
1answer
86 views

Seeking intuitive explanations regarding $A_{n-1}$ singularities

I am studying Ben Craps' lecture notes Big Bang Models In String Theory for my undergraduate thesis. I am not well versed in topology, and would like intuitive explanations for certain ideas regarding ...
0
votes
1answer
78 views

Can branes in string theory be described by different systems of mathematics or logic?

Mathematically, in string theory, branes can be described using the notion of a category and the mathematical category theory says that logic can change from one category to another. We can build ...
6
votes
1answer
167 views

D8 branes in M-theory

The following table gives us the correspondence between objects in Type IIA Superstring theory and M-theory: The D6 brane is magnetically dual to the D (10-6-4) = D0 brane and so magnetically couples ...
3
votes
2answers
104 views

Does an infinitely large thin plate produce a uniform $g$-field near its surface according to GR?

I had an argument with contributor @safesphere regarding this problem. He insists that an infinitely large plate with a finite surface density of $\sigma$ would eventually collapse into a black hole ...
3
votes
1answer
136 views

Why is the Polyakov action special for $p\!=\!1$ branes?

Reading this article I ran into a doubt. It derives the Polyakov action for a general $p$-brane $$S(X,g)=-\frac{T}{2}\int\text{d}^{p+1}\xi\,\sqrt{-g}\left(g^{ab}h_{ab}-(p-1)\right)\tag{7}$$ by ...
4
votes
2answers
207 views

2 coinciding D-branes leads to a $U(2)$ gauge theory

I'm having trouble understanding how two D-branes leads to a $U(2)$ gauge theory from David Tong's notes, chapter 7, pages 191-192. I am learning group theory and I understand that a 'charge' is a ...
1
vote
1answer
133 views

Scattering amplitude of open + closed strings and D-Branes

When calculating the scattering amplitude of $n$ open string tachyons and $m$ closed string tachyons on the disk, I'd like to understand why choosing the open string tachyons to be attached to $D_{25}$...
2
votes
1answer
88 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 ...
3
votes
0answers
118 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 ...
5
votes
1answer
126 views

D-brane analogue in ordinary QFT

I am reading David Tong's lectures on string theory and on the page 180 in chapter 7 of his lecture notes http://www.damtp.cam.ac.uk/user/tong/string.html : he claims that D-branes are something in ...
1
vote
1answer
77 views

How do branes come into existence according to string theory? [closed]

How do branes come into existence according to string theory? Also what are branes made out of?
2
votes
1answer
76 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 ...
1
vote
0answers
133 views

What is NS5 brane?

NS5 brane can be considered as 1/2 BPS solution in supergravity (with other solutions to compare): This branes of Type IIA/B supergravity are expected to extend to solutions of the full Type IIA/B ...
6
votes
2answers
344 views

Path integral for fermion on circle

I am trying to understand talk by Edward Witten Nonsupersymmetric D-Branes and the Kitaev Fermion Chain. More concretely, I wanna to understand this slide: If I try to calculate such path integral I ...
1
vote
0answers
33 views

Conformal symmetry extension for super p-branes?

Conformal symmetry plays a vital role in string and superstring theories. Why can not we generalize conformal symmetry to objects of greater dimensions as branes? Where are we with this puzzle in 2020?...

1
2 3 4 5 6