A class of theories that attempt to explain all existing particles (including force carriers) as vibrational modes of one-dimensional objects.
3
votes
0answers
124 views
Inclusion of information about external particles to calculate scattering amplitudes
In this (schematic) equation to calculate the scattering amplitude A by integrating over all possible world sheets and lifetimes of the bound states
$$ A = \int\limits_{\rm{life time}} d\tau ...
0
votes
0answers
106 views
P-adic Numbers and Eternal Inflation
In October(??) 2011, Leonard Susskind gave a talk and with few other people wrote papers about p-adic numbers and measure problems in cosmology, see e.g. arXiv:1110.0496. Has there been any recent ...
1
vote
2answers
187 views
How exactly do superstrings reduce the number of dimensions in bosonic string theory from 26 to 10 and remove the tachyons?
In bosonic string theory, to obtain the photon as the first excited state, the ground state must have a negative mass (tachyon). By applying $1 + 2 + 3 + \cdots = -1/12$, it can be shown (in a ...
1
vote
1answer
143 views
Are the sound waves from fundamental strings impossible to interact with?
Edited the question thanks to some helpful commenters.
Are the sound waves emitted by fundamental strings so small as to be impossible to interact with the world? In other words, do they disappear, ...
5
votes
0answers
137 views
An use of the Schwinger-Dyson equation
I was confused as to how the equation 10 on page 7 or equation 21 on page 8 of this paper http://arxiv.org/abs/1211.1866 was derived. Can someone explain from where does this come and what do the ...
1
vote
1answer
96 views
What are all the approaches that have been tried for a theory of quantum gravity? [closed]
I am aware that that the most researched approach is that of string theory. I have also heard about quantum loop gravity. What other approaches are there to unify gravity and QFT? Also, please include ...
2
votes
2answers
479 views
The meaning of multiverse
A) I am intrigued by the multiverse theory as mentioned in Stephen Hawking's new book, "The Grand Design". According to his theory, one can have different 'universes' in one ultimate existence, a ...
5
votes
0answers
51 views
paper about black branes and implications to 4d black holes
This paper makes a case for piezoelectric response (electric dipole moment under mechanical oscillations) of black branes. This paper does not make an implication of their results for 4D black holes ...
12
votes
7answers
962 views
What are the strings in string theory made of?
This is a follow-up to an intriguing question last year about tension in string theory.
What are the strings in string theory composed of?
I am serious. Strings made of matter are complex objects ...
2
votes
2answers
158 views
Identification of extended quantum objects?
In some physics theories like string theory we have notion of spatially extended quantum objects - strings, membranes etc. Assuming that such objects exist, how would they appear in experiments ? More ...
3
votes
0answers
116 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 ...
5
votes
2answers
413 views
What is background independence and how important is it?
What is background independence and how important is it?
In order to be a theory of everything, will the final string-theory/m-theory have to be background independent?
Does the current lack of ...
2
votes
1answer
138 views
Tachyon vertex operator (Polchinski's book)
I would like to know how does Polchinski in his book "derive" what is the "tachyon vertex operator" (..as say stated in equation 3.6.25, 6.2.11..) I can't locate a "derivation" of the fact that ...
2
votes
0answers
43 views
Do unoriented strings possess asymptotic states?
In QFT based particle theory, SU(N)-colored particles are not really present as asymptotic states, then raising some problems to build a S-matrix or other more axiomatic approaches to the theory.
...
13
votes
1answer
404 views
Multi-loop beta function of gauge theory (*without* Feynman diagrams)
I would like to point to the beautiful section 4.3 (page 42) of these lecture notes. I think this is the most educative exposition I have ever seen anywhere about Yang-Mill's beta function. What I ...
2
votes
1answer
165 views
Why does the universe exhibit three large-scale spatial dimensions? [duplicate]
Possible Duplicate:
Is 3+1 spacetime as privileged as is claimed?
Regardless of your favorite theory of how many dimensions the universe has in total, the universe seems to have a deep ...
0
votes
0answers
36 views
why is the modelisation of elementary particle as a two dimensional object in contradiction with General Relativity?
This is asserted by Trinh Xuan Thuan in his book "Chaos & Harmony" chapter String theory.
1
vote
1answer
196 views
Quantization of Nambu–Goto action in multiples of Planck's constant?
Isn't it possible? Quantization of Nambu–Goto action
$$\mathcal{S} ~=~ -\frac{1}{2\pi\alpha'} \int \mathrm{d}^2 \Sigma \sqrt{{\dot{X}} ^2 - {X'}^2}~=~nh\qquad n \in\mathbb{Z}.$$
3
votes
1answer
374 views
Recent Higgs boson observation and credibility of superstring theories
Data are coming in, and it seems that recent Higgs boson observation is eliminating many SUSY models. If so, what is happening to superstring theories, like M-theory?
2
votes
0answers
73 views
M-Theory: Are the branes still colliding and matter is being produced into our universe?
In M-Theory membranes are rippling in the 11th dimension and when they collided the bing bang happened and the ripples produced matter, is it still happening and matter is still being produced?
...
8
votes
2answers
417 views
What is the physical interpretation of the S-matrix in QFT?
A few closely related questions regarding the physical interpretation of the S-matrix in QFT: I am interested in both heuristic and mathematically precise answers.
Given a quantum field theory when ...
2
votes
1answer
83 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 ...
3
votes
0answers
259 views
How do the Einstein's equations come out of string theory?
The classical theory of spacetime geometry that we call gravity consists of the Einstein equation, which relates the curvature of spacetime to the distribution of matter and energy in spacetime.
for ...
8
votes
1answer
506 views
Is String Theory formulated in flat or curved spacetime?
String Theory is formulated in 10 or 11 (or 26?) dimensions where it is assumed that all of the space dimensions except for 3 (large) space dimensions and 1 time dimension are a compact manifold with ...
4
votes
1answer
128 views
Why Must Conserved Currents of Lorentz Symmetry Satisfy the Lorentz Algebra
I've seen it written many times that the commutation relation
$[M^{I-},M^{J-}]=0$
is required for Lorentz invariance in the light cone gauge quantisation of the bosonic string. This follows ...
2
votes
1answer
113 views
How exactly are the different motions of only one kind of fundamental string assumed to give rise to the spectrum of elementary particles we observe?
In string theory, it is assumed that all particles can be described as quanta corresponding to the excitations of only one kind of fundamental string.
How can in principle the different motion ...
14
votes
2answers
461 views
Does the exact string theory $S$-matrix describe all physics there is?
Suppose someone manages to evaluate the string theory $S$-matrix to all orders for any and all vertex operator insertions including non-perturbative contributions from world-sheet instantons and ...
0
votes
0answers
106 views
Colliding bubbles in hyperspace
Assuming the following
A universe is the surface from a bubble in hyperspace.
Inside a bubble there is nothing, only the surface represents a
universe. The size of the bubble is time.
Dark matter ...
1
vote
1answer
274 views
Branes Collision -> Big Bang
Imagine universe occurred when two parallel branes collided, Momentum of Branes converted to big bang kinetic energy after Collision. Thus, high-energy quanta are high-Vibrating strings.
what ...
3
votes
1answer
103 views
What interaction does a Fayet-Iliopoulos coupling parameterize the strength of?
Couplings give the strength of interactions. They appear in a Lagrangian as a coefficient to the two (or more) interacting fields. Unfortunately, I'm struggling to find a source that describes what it ...
0
votes
0answers
400 views
Are there any list of String Theory Equations? [closed]
I Google it but did not find anything.
here is a list of QM Formuals and a list of relativistic equations
Are there any list of String Theory Equations?
4
votes
1answer
81 views
Negative open string norms after BRST cohomology?
The question Disappearance of moduli for condensate of open strings made me think.
Suppose we have a Dp-brane completely wrapped over a $T^d$ compactification with $p\leqslant d$. Look at an open ...
3
votes
0answers
309 views
Isn't a single Quantum one single string? [duplicate]
In physics, a quantum (plural: quanta) is the minimum amount of any physical entity involved in an interaction.
In Quantum Mechanics There is no difference between one Quantum to another one.
...
2
votes
0answers
85 views
Can decompactification explain the inflation of the early universe?
I've just reread chapter 11 of this book where it is explained among other things, that our four dimensional universe could be unstable concerning a decompactification transition, since potential ...
2
votes
5answers
128 views
Why is the world sheet of an open string a cylinder?
I went to a lecture a few weeks ago and was told the following:
The world sheet of a closed string is a normal, standing cylinder.
The world sheet of an open string is a cylinder on its side.
This ...
6
votes
1answer
103 views
Disappearance of moduli for condensate of open strings
Consider a Dp-brane. Compactify $d$ spatial dimensions over a torus $T^d$. Suppose $d\geqslant p$, and that the Dp-brane is completely wrapped around the compactified dimensions.
Look at the open ...
1
vote
0answers
102 views
Extending General Relativity with Kahler Manifolds?
Standard general relativity is based on Riemannian manifolds.
However, the simplest extension of Riemannian manifolds seems to be Kahler manifolds, which have a complex (hermitian) structure, a ...
5
votes
1answer
276 views
Reference for mathematics of string theory [closed]
I have a great interest in the area of string theory, but since I am more focused on mathematics, I was wondering if there is any book out there that covers mathematical aspects of string theory. I ...
0
votes
0answers
85 views
Naive Uncertainty principle for string theory
Is it possible, in some sense, that a naive uncertainly principle for string theory could be expressed as :
$$ \Delta x_i \Delta p_j \Delta \sigma ~=~ \delta_{ij} \hbar \ell_s$$
where $\ell_s$ is ...
3
votes
1answer
219 views
Mathematical definitions in string theory
Does anyone know of a book that has mathematical definitions of a string, a $p$-brane, a $D$-brane and other related topics. All the books I have looked at don't have a precise definition and this is ...
0
votes
1answer
167 views
Which theory is closest to Theory of Everything? [closed]
To present, Which theory is closest to Theory of Everything? In the future, it probably including into Theory of Everything.
Can you describe more detail or attach links that I can reading after?
2
votes
1answer
149 views
what does holographic principle from string theory say about the possibilities of wormhole travel?
Is travel through stable macroscopic wormholes between remote points of spacetime going to be possible in a definitive theory of gravity, be it string theory or something beyond it?
Physicists level ...
6
votes
2answers
261 views
Is there stringy Morse theory?
This question is pretty vague and open. I'm just curious if anyone has considered this.
Morse theory has a nice physical formulation: a Morse function can be thought of as a potential, so the ...
2
votes
1answer
188 views
't Hooft limit of coupling fundamental fermions to Chern-Simons theory
This question is in reference to this paper: arXiv:1110.4386 [hep-th].
I would like to know what is the derivation or a reference to the proof of their crucial equation 2.3 (page 12).
In their ...
2
votes
0answers
58 views
Schwarzschild radius in matrix models
The Schwarzschild radius for 11D BHs is given by $l_{11}(l_{11}m)^{1/8}$, which is the special case ($D=11$) of the general dimensional case of $(G_Dm)^{\frac{1}{D-3}}$. Here $m$ is the BH mass and ...
7
votes
2answers
143 views
Embedding of $F(4)$ in $OSp(8|4)$?
Is the superconformal algebra in five dimensions, $F(4)$, a subalgebra of the (maximal) six-dimensional superconformal algebra $OSp(8|4)$?
0
votes
0answers
145 views
Riemann Hypothesis and String [closed]
I believe that this is a math's question, but
what is the connection between RIEMANN HYPOTHESIS or RIEMANN ZEROS and String Theory ??
2
votes
1answer
112 views
M-theory on a Planck scale torus
We know that 11D M-theory is described by BFSS matrix model and for M-theory on a torus $T^p$ (at least for small $p$s) the description is given by SYM theory in $p+1$ dimensions by using the ...
2
votes
0answers
84 views
Superstring theory and renormalization [duplicate]
Possible Duplicate:
Does the renormalization group apply to string theory?
Renormalization in string theory
QED and some quantum theories require renormalization techniques and take it as ...
3
votes
1answer
375 views
The Universe is a Hologram
First my background: no physics, but Ph.D. in math. I was reading this article on Slashdot. It links to this Wikipedia page. The content of the Slashdot article is that some physicists believe the ...
