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.

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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 ...
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1answer
241 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 $D1$ ...
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102 views

Are M branes fundamental?

In M theory, are M branes fundamental or are they made of something else? Are they made up of fields? Say for instance the M2 brane is not fundamental, wouldn't that mean that the string is not ...
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1answer
182 views

Klebanov-Witten and Conifold equation

I'm a bit confused by some that is understood in the following papers: 1 and 2. I understood that there is a GLSM with fields $A_i,B_i$ with $i=1,2$ whose moduli space is the conifold described with ...
2
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0answers
77 views

Can fractional D-branes be described in F-theory?

In Type IIB string theory, there can exist fractional D-branes at singularities. Additionally, F-theory is in some sense an alternative description of Type IIB string theory. So there should be an F-...
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1answer
73 views

Spinning particle lagrangians [closed]

What is the most general relativistic and non-relativistic lagrangian describing a spinning object in the following cases? Classical point particles. "Classical" point super-particles.
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1answer
555 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 ...
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1answer
131 views

Can the D3 brane be described by M theory?

M theory has only 2 fundamental objects, the M2 and M5 brane. These can describe a variety of different branes. However, is there any description on how M theory describes D3 branes?
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66 views

Orthogonal gauge theory on branes and orientifolds

Consider a stack of $n$ $D3$ branes in type IIB string theory. The gauge theory on the world-volume has gauge group $U(n)$. Consider now a stack of $n$ $D3$ branes on top of an orientifold plane $...
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351 views

Open conjectures on the Fukaya category

This is ported from mathoverflow question https://mathoverflow.net/q/263693/. Can somebody give examples to open conjectures on the behavior of the $Fuk(M,ω)$ (that's the "mathematical A-model ...
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1answer
291 views

Higgs Mechanism on Parallel Separated D-Branes

I do understand the intuitive logic behind the Higgs mechanism for parallel D-branes that are separated by a distance $x$, but I would like to see a more quantitative argument. Is it possible to ...
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Question about Duality between F-theory on elliptically fibered K3 and Heterotic/Type-I on T^2

I'm studying Sen's paper ``F-Theory and Orientifolds'' [arXiv:hep-th/9605150] where he discusses the duality between F-theory on an elliptically-fibered K3 and heterotic/type-I string theory on a two-...
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51 views

How does the curved spacetime look on both sides of an infinite massive plate with constant mass density?

On both sides of a massive plate with constant mass density, the gravitational force is uniform. How does the curved spacetime corresponding to such a uniform field look like? Because the field is ...
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1answer
219 views

Are there membrane theories beyond string theory? [duplicate]

String theory uses a Feynman diagram with surfaces instead of lines, and world sheets instead of world lines. Can there be theories with solids instead of surfaces and world solids instead of world ...
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170 views

Interpretation of Dynkin diagrams

I am having trouble in understanding the physics represented by dynkin diagrams. Say I have the following diagram: What is the difference between the square nodes and circular nodes? What does the ...
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1answer
125 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 ...
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85 views

Finding the Hilbert expansion of a D4 Coulomb branch

I am trying to compute the HS of the following Coulomb branch, but first I am not sure how to proceed in interpreting the diagram and what variables to use. I am trying to use the equation from this ...
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97 views

Bounds on the volume of A branes in Fano varieties

I have been recently reading "String theory and M theory: a modern introduction" of Becker et al. They consider type IIB string theory compactified on Calabi Yau threefold $X$ with a nowhere vanishing ...
4
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1answer
269 views

M-theory with its 3-form $H$ and the problem of having no Lagrangian

This is a standard question about the M-theoretic construction of the 6d (2,0) theory. This is done, in the simplest case, by an M2 brane hanging between two M5 branes. The theory on the M5 branes is ...
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1answer
213 views

Charge of an orientifold plane

Orientifold projection of open-string states (with $SO(32)$ Chan-Paton charges) of IIB superstring theory is said to result in an orientifold 9-plane with $\pm 16$ D9 brane charge. My question is why ...
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1answer
230 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 $\Sigma$ ...
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2answers
203 views

Composite black hole structures

Could a system of black holes form a "black" structure that has physical dimensions? For instance, could a series of black holes in the same orbit around an object form a black torus?
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2answers
123 views

What are the evidence that gravitational force act across all spatial dimensions?

I keep hearing in the folk theory of physics that gravitational force (if a force it indeed is) will act across parallel universes or higher spatial dimensions. Where did this idea come from? Does it ...
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1answer
94 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 ...
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130 views

D-brane wrapping in the geometric transition for type-IIB on a Calabi-Yau manifold

In Stefan Metzger's thesis (https://arxiv.org/abs/hep-th/0512285) on page 9, the following statement appears in connection with the compactifications type-IIB string theory on two Calabi-Yau manifolds ...
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1answer
499 views

What are the branes in M-theory?

In M-theory, our universe is a brane. But this brane is 2-dimensional, so how does our universe fit in? Is our universe just a part of the brane?
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73 views

D0-branes in two-dimensional ${\cal N}=(2,2)$ Landau-Ginzburg models at critical points of the superpotential

My question concerns Section 6.1 of Hori's 'Linear Models of Supersymmetric D-branes' (http://arxiv.org/abs/hep-th/0012179). Firstly, some background. The quantum field theory in question is a 2d ${...
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272 views

5-branes in Topological String Theory (TST)

It is known that the topological A-model allows the existence of $\frac{1}{2} \left[ D + \mathrm{rank} \left( B \right) \right]$-dimensional branes, where $D$ is a dimensionality of spacetime, and $B$ ...
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2answers
203 views

quantizing open strings on Dp-branes

I am wondering what happens if we quantize open strings in the presence of Dp-branes. I'm sure lots of people did all the calculation before, but my question is about the physical meaning behind those ...
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0answers
96 views

Twisted Bianchi identity for D6-branes from M-theory?

The descent of the M2/M5-brane charges to the Dp-brane charges and their twisted Bianchi identites $\mathrm{d} F_{p+2} = H_3 \wedge F_p$ is straightforward for $p = 0,2,4$. (This is spelled out ...
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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?
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42 views

What does “Field theory limit” means in D/M-branes or supergravity theories? [closed]

What does "Field theory limit" means in D/M-branes or supergravity theories? Reading some papers related with D/M-branes, they often mention field theory limit, $i.e$, limit of $\alpha\rightarrow 0$,...
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1answer
202 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 ...
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1answer
372 views

How many orientifold planes does one need?

According to the book ''String Theory in a Nutshell'' by Elias Kiritsis (page 204, linked here), the tension of an $Op$-plane is $$T_{Op} = -2^{p-4}T_{Dp}$$ With this picture, one gets -- for type ...
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146 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 ...
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2answers
317 views

Multi-center Taub-NUT geometry and homologically nontrivial cycles

In the string theory book by Ibanez and Uranga (click here for the Google books excerpt), the four-dimensional multi-center Taub-NUT metric is written as $$ds^2 = \frac{V(\textbf{x})}{4}d\textbf{x}^2 +...
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0answers
56 views

Query about Ramond-Ramond fluxes associated with a Dp-brane

A paragraph in the string theory book by Ibanez and Uranga (String Theory and Particle Physics by Luis Ibáñez and Angel Uranga) has confused me. According to the book (for a screenshot of the ...
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1answer
564 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 $\mathbb{R}^{...
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1answer
140 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 ...
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75 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 ...
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1answer
228 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 ...
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1answer
218 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, ...
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1answer
384 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 ...
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0answers
115 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 ...
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1answer
345 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 II ...
3
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1answer
504 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 ...
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1answer
326 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 ...
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1answer
334 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 ...
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0answers
123 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 ...
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43 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 $a$?