A class of theories that attempt to explain all existing particles (including force carriers) as vibrational modes of one-dimensional objects.
-5
votes
0answers
52 views
Criticism of String Theory by other string theorists [closed]
*EDIT: Due to policy I will edit this into a question:
Do you know any string theorist that have criticized string theory and if so please could you give me references? thanks.
End of EDIT. ...
4
votes
1answer
43 views
T-Duality between Type HE String theory and Type HO string theory
My question is regarding T-Duality between the 2 Type H string theories.
I know that the Type II String theories are T-dual to each other because T-Duality changes the sign of the Gamma Matrix so
...
0
votes
0answers
77 views
How can it be seen that ST unifies GR and QM as the quantum gravity scale is not directly accessible
I am a newbie to superstring theories, but I came into this question:
so superstring theories purport to unify general relativity and quantum theory.
However, there is yet no definitive way to test ...
3
votes
1answer
41 views
Question on Type HO/HE string theory
The Heterotic string state is a tensoring of the bosonic string left-moving state and the Type II string right-moving state. Therefore, I expect the spectrum to be:
$$\begin{array}{*{20}{c}}
\hline
...
2
votes
2answers
76 views
Question on the Hagedorn tower in Type I string theory
In a previous question (Mass spectrum of Type I string theory), I had asked about the mass spectrum of Type I string theory. I got a response saying that it is a Hagedorn tower. However, my source ...
15
votes
3answers
917 views
Is decoherence even possible in anti de Sitter space?
Is decoherence even possible in anti de Sitter space? The spatial conformal boundary acts as a repulsive wall, thus turning anti de Sitter space into an eternally closed quantum system. Superpositions ...
2
votes
1answer
88 views
Energy Functional
I am a graduate student in pure mathematics, during my study on Ricci Flow I faced some functional known as energy functional. For example Einstein-Hilbert functional is called an energy functional, ...
7
votes
4answers
1k views
Number of dimensions in string theory and possible link with number theory
This question has led me to ask somewhat a more specific question. I have read somewhere about a coincidence. Numbers of the form $8k + 2$ appears to be relevant for string theory. For k = 0 one gets ...
6
votes
1answer
248 views
Mathematical concept of supersymmetry
I wish to study supersymmetry in field theory(sometime in december). However, I am quite not sure what is needed for its study. In supersymmetry, I just want to get the mathematical idea, such as its ...
5
votes
2answers
122 views
How can string theory work without supersymmetry?
This question is inspired from reading Mitchell Porter's nice answer here to a question asking why supersymmetry should be expected naturally. Among other things, he explains that since weak scale ...
2
votes
1answer
68 views
Flavour diagonal SUSY breaking
Because there is a single Yukawa matrix for the SM leptons, the lepton mass and flavour states can be aligned, by diagonalization, even if the Yukawa matrix had off-diagonal elements.
SUSY breaking, ...
9
votes
1answer
257 views
How do I find constraints on the Nambu-Goto Action?
Let $X^\mu (t,\sigma ^1,\ldots ,\sigma ^p)$ be a $p$-brane in space-time and let $g$ be the metric on $X^\mu$ induced from the ambient space-time metric. Then, the Nambu-Goto action on $X^\mu$ is ...
7
votes
0answers
327 views
+100
About defining “baryons” and “mesons”
I want to understand the proof of the claims (of the construction as well as of its uniqueness) of gauge singlet states given around equation 2.13 (page 10) of this paper.
Also does the listing of ...
3
votes
1answer
56 views
Gauging discrete symmetries
I read somewhere what performing an orbifolding (i.e. imposing a discrete symmetry on what would otherwise be a compactification torus) is equivalent to "gauging the discrete symmetry". Can anybody ...
2
votes
0answers
48 views
About deriving the multi-trace index in terms of the single-trace index
This question is in reference to this paper
Combining their equations 5.2, 5.3, 5.6 and 5.7 one seems to be looking at the integral/partition function,
$Z(x) = \prod_{n=1}^{n =\infty}\left [ \int ...
2
votes
0answers
49 views
Mass spectrum of Type I string theory
I understand that the massless fields of the Type I string theory are the described by:
[\begin{array}{*{20}{c}}
{{\rm{Sector}}}&{{\rm{Massless fields}}}\\
{{\rm{R - R}}}&{{C_0}}\\
{{\rm{NS - ...
4
votes
2answers
235 views
Fundamental equation(s) of string theory?
I often hear about string theory and its complicated mathematical structure as a physical theory, but I can't say that I've ever actually seen any of the related math. In general, I'm curious as to ...
4
votes
2answers
211 views
SUSY's Critical role in String Theory
In many popsci articles it is claimed that String Theory (ST) birthed SUSY. Yet ST was originally invented as a bosons-only theory, that later on brought fermions into the fold. This was only ...
1
vote
1answer
449 views
What is the smoking gun signature of string theory?
What is the smoking gun signature of string theory? Suppose we have a complete and consistent model of quantum gravity with a zero or negative cosmological constant, but all we are given is its ...
3
votes
1answer
62 views
Spectra of the Type II String theories
The spectrum of the Type II string theory (both IIA and IIB) is given by:
\begin{array}{*{20}{c}}
\hline
& {{\text{Sector}}}& & {{\text{Spectrum}}}& & {{\text{Massless Fields}}} ...
3
votes
0answers
94 views
Holonomy twisting
There is Witten's topological twist of standard SUSY QFTs with enough SUSY into Witten-type TQFTs. What is a holonomy twist?
2
votes
0answers
38 views
Construction of the supergravity side explicitly in gauge/gravity dualities
Although the motivation of this question comes from the AdS/CFT correspondence, it actually is related to a more general principle of gauge/gravity duality. We know from Maldacena's conjecture that a ...
6
votes
1answer
78 views
Critical dimension in quantization of p-branes
So I have what might be a fairly basic question, but my understanding that in the quantization of the the string, or the 1-brane, there are conditions on the number of spacetime dimensions to ensure ...
10
votes
1answer
385 views
Why one-dimensional strings, but not higher-dimensional shells/membranes?
One way that I've seen to sort-of motivate string theory is to 'generalize' the relativistic point particle action, resulting in the Nambu-Goto action. However, once you see how to make this ...
1
vote
2answers
145 views
Where does quantum mechanics come from? [closed]
Where does quantum mechanics come from?
If string theory is proved to be the correct quantum theory of gravity but it failed to explain where quantum mechanics came from can we still consider it a ...
2
votes
0answers
26 views
Is there a critical order of the Abelian gauge theory in (2+1)D
In (2+1)D spacetime, it is known that the $U(1)$ gauge theory is always confined (according to Polyakov), while the $\mathbb{Z}_2$ gauge theory can support a deconfined phase. Now consider a generic ...
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 ...
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 ...
22
votes
10answers
5k views
Discreteness and Determinism in Superstrings?
So Gerard 't Hooft has a brand new paper (thanks to Mitchell Porter for making me aware of it) so this is somewhat of a expansion to the question I posed on this site a month or so ago regarding 't ...
2
votes
0answers
26 views
``integrated vertex operators" in 1-loop open/closed bosonic string amplitude
This question is in reference to the first ~15 minutes of this String Theory lecture by Prof.Shiraz Minwalla,
http://theory.tifr.res.in/Videos/strings28_24sep08.mp4
Can one give a reference ...
12
votes
0answers
201 views
Anomalous target space diffeomorphisms for one-loop world-line integrals
The Schwinger effect can be calculated in the world-line formalism by coupling the particle to the target space potential $A$.
My question relates to how this calculation might extend to computing ...
8
votes
2answers
319 views
Heterotic string as worldvolume theory of two coincident 9-branes in 27 dimensions?
The heterotic string is a combination of right-moving excitations from a D=10 superstring and left-moving excitations from a D=26 bosonic string, with the left-movers behaving as if the extra 16 ...
2
votes
3answers
271 views
Could all strings be one single string which weaves the fabric of the universe?
This question popped out of another discussion, about if the photon needs a receiver to exist. Can a photon get emitted without a receiver? A universe containing only one electron was hypothetically ...
5
votes
0answers
238 views
Can the laws of quantum mechanics be derived from a more fundamental theory? [closed]
String theory takes quantum mechanics for granted and tries to make it compatible with gravity but if it turns out to be a theory of everything then shouldn't it in principle explain why our world is ...
0
votes
1answer
102 views
Relation between Higgs boson and force of gravitation
I don't know and I can't handle it. I am so much curious about the recent discoveries in science. European Space Agency and NASA are doing great work. Hats up to these institutions. My nights are ...
8
votes
8answers
2k views
What are cosmological “firewalls”?
Reading the funny title of this talk, Black Holes and Firewalls, just made me LOL because I have no idea what it is about but a lively imagination :-P (Sorry Raphael Bousso but the title is just too ...
0
votes
0answers
104 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
0answers
39 views
A three string tree diagram evaluated in CFT is different from string field theory evaluation
Hi Guys generally when you evaluate the 3 open string tachyon tree level amplitude in CFT, you do a conformal transformation mapping the worldsheet to the upper half of the complex plane and the ...
5
votes
1answer
59 views
AdS/RCFT examples?
RCFT's (rational conformal field theories) in two dimension are very well-studied, but it seems that there is no any gravity dual of such theories has been found. Is there example of the holographic ...
2
votes
0answers
50 views
Standard Quantum Mechanics representation as a constrained 2 + 1 space-time (membrane) theory?
Could a particular Standard Quantum Mechanics representation be a constrained 2 + 1 space-time theory (membrane theory) ?
(i) This question is motivated by a possible (approximative) analogy with ...
3
votes
1answer
90 views
Supersymmetry and non-compact $R$-symmetry group?
The $R$-symmetry for $N$ supercharges is $U(N)$. Is it possible to generalize $R$-symmetry [let's take $U(4)$) to be something like $U(2,2)$ (maybe analogous to Wick rotation of $SO(3,1)$ to ...
-3
votes
0answers
43 views
What is string tension in quark confinement? [closed]
What is string tension?
is it real or just an idea?
What is, its amount?
i've heard that string tension increase $a_s$, why?
2
votes
2answers
250 views
Correlation functions in thermal field theory etc
Suppose I am studying a field theory at finite temperature or some black hole formation scenario from boundary theory perspective in the sense of AdS/CFT. How is it possible to gain information about ...
2
votes
1answer
52 views
Question about charge conservation at vertices of web diagram
My question is about web diagram in paper of Aganagic et al.
How to get the $\alpha-\beta$ line rather than $-\alpha+\beta$ line of rightmost diagram of fig.3?
More precisely, how to show the charge ...
5
votes
1answer
113 views
Starting examples of Maldacena duality
I would like to know of what are the simplest/starting/basic examples that a student can work through to learn (and to convince oneself!) that AdS/CFT really works? I would like to know of the basic ...
2
votes
3answers
269 views
What does this “Witten's Dog” Feynman diagram in Futurama episode mean? [closed]
In an old episode ("Mars University") of Futurama which is a TV show, a character named Professor Farnsworth was trying to lecture "Superdupersymmetric String Theory" and "Witten's Dog" to some ...
-5
votes
0answers
60 views
Consequences of Third Postulate of Special Relativity [closed]
Consequences of SR arise from two postulates.
know as this abstract states:
"relativistic action is limited to planck's constant", and maybe we've to consider it as the possible third postulate of ...
14
votes
2answers
457 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 ...
3
votes
1answer
117 views
Why does in string theory the amount of supersymmetry have to be $\cal{N} \leq 2 $?
Why is this, that in string theory the maximum amount of supersymmetry is $\cal{N} = 2$, whereas in supergravity one can have up to $\cal{N} = 8$ ?
3
votes
0answers
62 views
What is kappa symmetry?
On page 180 David McMohan explains that to obtain a (spacetime) supersymmetric action for a GS superstring one has to add to the bosonic part
$$
S_B = -\frac{1}{2\pi}\int d^2 \sigma ...
