A class of theories that attempt to explain all existing particles (including force carriers) as vibrational modes of extended objects, such as the 1-dimensional fundamental string.

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69 views

Is there a relation between the weak scale and the intermediated string scale?

I was reading these papers http://arxiv.org/abs/hep-th/0609180v2 http://arxiv.org/abs/hep-th/0610129v2 They state that $m_s$ is proportional to $M_P/\sqrt{V} $ and that $m_{3/2}$ is proportional to ...
2
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0answers
40 views

Why does the object $\epsilon_L Q_L + \epsilon_R Q_R$ correspond to a 16-component conserved supercharge when we have a Dp-brane?

I understand that when a 10-dimensional superstring theory has a Dp-brane (say, extending in the $x_0, ... , x_p$ directions) we have the total conserved supercharge given by: \begin{equation} ...
3
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33 views

Quiver and Gauge theory

i want to know how to construct a quiver of a Gauge theory specified by groupe g with rank=r ?
3
votes
1answer
89 views

Even-branes in IIA and odd-branes in IIB

The R-R sector of IIA and IIB are respectively given as, $8_s \otimes 8_c = [1]\oplus [3] = 8_v \oplus 56_t$ $8_s \otimes 8_s = [0]\oplus [2] \oplus [4]_+ = 1 \oplus 28 \oplus 35_+$ Now looking at ...
3
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0answers
93 views

What is the theoretical geometry of bubble universes?

My research has led me to look into the idea of bubble universes which I don't know very much about. The first thing that I am looking for is understanding or visualising how could many bubbles ...
5
votes
1answer
165 views

String theory in the context of quantization prescriptions

My new question here: has string theory been analyzed somewhere in the context of various quantization prescriptions formulated in a mathematically sound way? I mean something like geometric ...
3
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0answers
34 views

What is the world-sheet picture of high energy open string scattering?

Following Gross-Manes paper (which came right after Gross-Mende), the planar one-loop amplitude (the annulus) is dominated by the region in moduli space where the radius of the annulus shrinks to a ...
1
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1answer
91 views

Canonical partner of time in QFT and string theory

In analytical mechanics, the Hamiltonian or total energy becomes the conjugate momentum of the time in the symmetric form of the equations. This seems very strange and interesting to me. Does it have ...
3
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0answers
77 views

Questions on entanglement entropy

If the spatial entangling surface is $M$ then it seems that one way to get the entanglement entropy is to think of the QFT on the manifold $S \times M$ where $S$ is a 2-manifold with the metric, ...
3
votes
1answer
50 views

A coincident stack of D3 branes vs a shell of them

I would in general like to understand how to derive the low energy metrics to describe D-brane configurations. Any pedagogic reference which explains the method? In particular I have in mind these ...
0
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1answer
172 views

So physicist's really do think the Universe could be a holographic Illusion?

http://www.nature.com/news/simulations-back-up-theory-that-universe-is-a-hologram-1.14328 http://guardianlv.com/2013/12/compelling-evidence-says-our-universe-is-a-hologram/ I thought the holographic ...
4
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1answer
62 views

Same partition functions, different theories

I am reading the book "Basic Concepts of String Theory" by Blumenhagen, Lust and Theisen and in page 290 they say: "It follows that the $E8\times E8$ and the $SO(32)$ heterotic string theories have ...
10
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3answers
1k views

AdS/CFT not dependent on validity of string theory

I have been told that the AdS/CFT correspondence proof does not rely on the validity of string theory. To be honest I don't know what to make of this. The idea of taking seriously the results of ...
3
votes
0answers
106 views

picture and isomorphisms

I found a paper by A. Belopolsky : "Picture changing operators in supergeometry and superstring theory" where he says there exists a possible physical state in one picture that doesn't exist in ...
7
votes
1answer
172 views

Ж (“zhe”) in string theory?

I was just recently watching a TED talk about string theory, by Thad Roberts, and at around 11:10 into the video he mentions a constant for maximum spacial curvature called "zhe" (the Cyrillic symbol ...
5
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1answer
83 views

Alternative Critical Dimensions in String Theory

Is it possible to write down a Lagrangian for a string theory with a critical dimension different than the familiar 10 or 26? How could one find a string theory Lagrangian for a given dimension? Could ...
6
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1answer
145 views

Is Poincare recurrence relevant to our universe?

If the theory of everything indicates a singularity-free and finite universe, will Poincare recurrence be relevant to the universe? If so, is there any interesting physical consequence, e.g. in ...
1
vote
1answer
103 views

Differential Operators in Polyakov Action

What do the differential operators in the Polyakov action mean? How does one derive the Polyakov action and treat the differential operators?
3
votes
1answer
106 views

Is mean field theory self-consistency analogous to string theory consistency?

My question is vague, so I'm hoping the answers will help me ask more concrete questions and maybe produce some interesting discussion. In mean field theory, say for the Ising model, we treat the ...
2
votes
2answers
106 views

Zwiebach quick calculation 2.5

I am working through Zwiebach's a first course in string theory. It's been a while since I did any math (or physics!), and I am stuck on the following problem (quick calculation 2.5 in the book): ...
5
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0answers
107 views

What is the physical interpretation of the Papadodimas/Raju mirror operators?

In this paper http://arxiv.org/abs/1310.6335, the authors discuss the firewall problem and contruct so called mirror operators appearing in the correlation function. The key part seems to be (2.6) ...
11
votes
3answers
300 views

about the Atiyah-Segal axioms on topological quantum field theory

Trying to go through the page on Topological quantum field theory - The original Atiyah-Segal axioms - "Let $\Lambda$ be a commutative ring with 1, Atiyah originally proposed the axioms of a ...
2
votes
1answer
100 views

How to get a $\mathcal{N}=2$ SuperYang-Mills Lagrangian from a quiver

How can one write down the $\mathcal{N}=2$ SuperYang-Mills Lagrangian given a quiver graph? For concreteness consider the quiver $$(2)-(4)-[6]$$ where the node $(2)$ corresponds to a $U(2)$ factor ...
5
votes
0answers
72 views

Commutator as a time-ordered product

I'm reading through Seiberg and Witten's paper "String Theory and Noncommutative Geometry," and one part in $\S$2.1 isn't quite clear to me. (Sorry, in advance, for the length.) My question is about ...
6
votes
1answer
169 views

Topological ground state degeneracy of SU(N), SO(N), Sp(N) Chern-Simons theory

We know that level-k Abelian 2+1D Chern-Simons theory on the $T^2$ spatial torus gives ground state degeneracy($GSD$): $$GSD=k$$ How about $GSD$ on $T^2$ spatial torus of: SU(N)$_k$ level-k ...
2
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0answers
46 views

Stringy corrections to Friedmann equation

Does anyone know a reference or a paper which discusses string theory correction to Friedmann equations?
3
votes
1answer
55 views

What is the need to consider a singular spacetime?

To have a consistent superstring theory (which is to avoid the conformal anomaly on the worldsheet CFT) we are forced to build our theory on the critical dimension $n=10$. However, the Standard ...
2
votes
1answer
65 views

How does a gauge theory probe a spacetime singularity?

Within the framework of string theory, I have read in numerous articles such as the introduction of this this in which it is stated that the gauge theories living on a stack of D-branes can be used to ...
2
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0answers
70 views

Regulating an infinite sum in the $bc$ CFT

The EM tensor of the $bc$-CFT is $$ T(z) = \colon \partial b c \colon - \lambda \partial \colon b c \colon $$ After expanding in a mode expansion, we find $$ T(z) = \sum_{m} \frac{1}{z^{m+2}} \sum_n ...
5
votes
1answer
79 views

Fundamental group of Calabi-Yau 3-fold in string theory

In string theory, we compactify a 10-dimensional space by a Calabi-Yau 3-fold to reduce the dimension to 4. To get a reasonable theory, a Calabi-Yau 3-fold should satisfy some properties. One is the ...
2
votes
1answer
129 views

S-Matrix, String theory, Matrix mechanics and Quantum Mechanics

I'm trying to learn theoretical physics up to string theory. I know linear algebra, calculus 1+2, complex analysis. I know the basics of homology, homotopy, group theory and differential geometry. Now ...
6
votes
1answer
279 views

Is Conformal Symmetry Local or Global?

I'm just brushing up on a bit of CFT, and I'm trying to understand whether conformal symmetry is local or global in the physics sense. Obviously when the metric is viewed as dynamical then the ...
3
votes
1answer
101 views

electric, magnetic and level quantization for a SU(N), SO(N) and a compact U(1) Chern-Simons theory

Imagine three different worlds describe by three theories (I), (II), (III). Theory (I) - compact U(1) Chern-Simons: A compact U(1) Chern-Simons theory with magnetic monopole charges $m_1$. ...
7
votes
0answers
95 views

Moduli Stabilization in 6D Einstein-Maxwell theory - Fluxes and O3 planes

I'd like to do the maths for the moduli stabilization of 6D Einstein-Maxwell Gravity $$ S= \int d^6X \sqrt{-G_6}(M_6^4R_6[G_6]-M_6^2|F_2|^2), $$ where the 6D metric is specified by $$ ds^2 = ...
15
votes
2answers
434 views

S-Matrix in $\mathcal{N}=4$ Super-Yang Mills

This is a general question, but what is meant when people refer to the S-Matrix of $\mathcal{N}=4$ Super Yang Mills? The way I understood it is the S-Matrix is only well defined for theories with a ...
10
votes
0answers
159 views

Orbifold CFT of SU(2)/G and SO(3)/G

In this paper by Dijkgraaf, Vafa, Verlinde, Verlinde, orbifold CFT is discussed. In that paper, it outlined that orbifold CFT provides a way to generate the new theories from the old known ones. ...
3
votes
1answer
65 views

What constrains ghost fields $c^+$ and $b_{++}$ as $z$ going to infinity

In Green's superstring theory, Chapter 3, from equation 3.3.13 to 3.3.18, the author says that the singularity behavior of the ghost field $c^+$ must be no faster than $z^2$ as $z$ goes to infinity. ...
3
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0answers
57 views

Normalizability of the Hartle-Hawking state in Liouville theory

I'm confused about how to normalize the Hartle-Hawking state in 2D quantum gravity. We can compute the HH state for two circles of length $\ell_1$ and $\ell_2$ in the matrix model as $\langle ...
4
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0answers
82 views

Applications of quarks or string theory? [closed]

We wouldn't have computers if we didn't know about quantum physics. I understand understanding of general relativity is needed to make GPS work well. Has knowledge of quarks or string theory resulted ...
6
votes
2answers
170 views

What happens if the holonomy group lies in $SU(2)$ for a CY 3-fold?

I am a mathematician and reading a physics paper about the holonomy group of Calabi-Yau 3-folds. In that paper, a Calabi-Yau 3-fold $X$ is defined as a compact 3-dimensional complex manifold with ...
3
votes
1answer
91 views

A question about T duality

Normally T-duality is introduced perturbatively by computing world-sheet spectrum of fundamental strings, and one of the conclusions is that it switches between momentum mode and winding mode of ...
2
votes
1answer
63 views

Explicit calculation of bosonic string Weyl invariance at one loop

I have been trying to do all the calculations in the Green, Schwarz and Witten Superstring Theory textbook. At the end of chapter 3, the author did one-loop calculation for Weyl invariance for the ...
0
votes
0answers
48 views

String Theory- Are strings the end? What are they made of? [duplicate]

Although I have informed myself in string theory through reading books and watching videos, I do not know or understand what superstrings are made of. History has definitely shown us that when we ...
3
votes
1answer
198 views

Does string theory pose a photon mass problem?

A few weeks ago, I started reading books on string theory. One thing that really seemed confusing or contradictory was that string theory explains that the energy of a superstring gives mass to the ...
4
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2answers
101 views

Proof that higher genus surface admits a metric of negative Ricci scalar everywhere

In the Green, Schwarz and Witten Superstring Theory textbook, the paragraph below equation 3.3.15 says, For genus greater than one, it can be shown that the surface admits a metric of everywhere ...
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1answer
79 views

How can a string be unidimensional if they can be open ended or close ended?

I just don't understand how a object with 2 ends can be unidimensional.
3
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1answer
65 views

Fourier Expansions for Closed Strings and Parity

I'm revising some string basics, and have come across the following problem. For closed strings one introduces the worldsheet parity operator $$\Pi : \sigma \mapsto \ell-\sigma$$ where $\ell$ is the ...
5
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0answers
163 views

What are the AdS/CFT papers which study the stringy effects in the bulk? [closed]

I would like to know of a list of pedagogical/classic/nice papers that study stringy effects in the bulk. May be a sequence which a student follows to understand the stringy nature that is at play.
3
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2answers
197 views

Does String Theory explain wave-particle duality?

Does string theory explain the weird things that happens at the quantum level, especially wave-particle duality?
4
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2answers
94 views

What is the experimental status of the G2-MSSM?

The G2-MSSM is supposed to be the low-energy theory of a hypothetical class of M-theory compactifications studied by some phenomenologists. It is just the MSSM, but in a particular region of parameter ...