A class of theories that attempt to explain all existing particles (including force carriers) as vibrational modes of one-dimensional objects.
5
votes
0answers
68 views
R charge of the chiral multiplet in $2+1$ dimensions
These are two examples that I am puzzled by,
One can see in this paper on page 16 that for ${\cal N} =2$ theory on $2+1$ the R-charge of the $\phi$ and the $\psi$ is determined to be $\frac{1}{2}$ ...
3
votes
1answer
184 views
Why do strings split in string theory?
In string theory, we are told strings can split and merge if the string coupling is nonzero, even while the worldsheet action remains Nambu-Goto or Polyakov plus a topological term. However, a ...
7
votes
3answers
899 views
PhD Research Areas in String Theory
I'm thinking of applying to do a PhD in String Theory, starting in September 2013. I'm gradually learning more about the subject through external reading, but still most papers are impenetrable! Could ...
2
votes
1answer
260 views
Wilson loops and gauge invariant operators (Part 1)
I guess the Hilbert space of the theory is precisely the space of all gauge invariant operators (mod equations of motion..as pointed out in the answers)
Is it possible that in a gauge theory the ...
5
votes
1answer
305 views
Taking the continuum limit of $U(N)$ gauge theories
I would like to draw your attention to appendix $C$ on page 38 of this paper.
The equation $C.2$ there seems to be evaluating the sum $\sum_R \chi _R (U^m)$ in equation 3.16 of this paper. I ...
2
votes
1answer
169 views
Why doesn't the anthropic principle select for N=2 SUSY compactifications with an exactly zero cosmological constant?
The party line of the anthropic camp goes something like this. There are at least $10^{500}$ flux compactifications breaking SUSY out there with all sorts of values for the cosmological constant. Life ...
0
votes
3answers
249 views
Laws of gravity for a universe that only consists of two objects?
So, we know that when two objects of normal matter get away from each other, the gravitational pull they feel from each other, decreases.
I wanted to see how that would work. And in my ...
3
votes
1answer
130 views
How could we experience multiverse through cosmic background radiation?
I'm reading a book about string theory, and it tells me in the future it could be possible to detect existence of other bubble universes through cosmic background radiation. Is this true? What could ...
1
vote
1answer
117 views
Superspace Uncertainty Principle
Do the "operator for translations in superspace" and the "position in superspace operator" follow an uncertainty principle? How "real" is superspace? Aside from being weird (and possibly just a ...
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 ...
1
vote
1answer
881 views
What's next after Higgs Boson discovery? [duplicate]
Possible Duplicate:
Practical matter of the Higgs-Mechanism
As everybody knows that the Higgs Boson was discovered on July 4th,2012, I am so curious about it.
What are the possible ...
3
votes
2answers
599 views
Why does string theory require 9 dimensions of space and one dimension of time?
String theorists say that there are many more dimensions out there, but they are too small to be detected.
However, I do not understand why there are ten dimensions and not just any other number?
...
1
vote
2answers
319 views
What Observations could undeniably support string theory?
What experiments could provide observable "stringy" effects.
All valid experiments are acceptable (also theoretical experiments).
4
votes
1answer
207 views
About 2+1 dimensional superconformal algebra
I would like to get some help in interpreting the main equation of the superconformal algebra (in $2+1$ dimenions) as stated in equation 3.27 on page 18 of this paper. I am familiar with supersymmetry ...
5
votes
1answer
3k views
How would the discovery of Higgs Boson affect superstring theories?
As we probably all know, a new particle similar to Higgs Boson has been discovered.
If this turns out to be true, standard model will get a boost (as the discovered mass almost equals to the ...
3
votes
1answer
179 views
Twistor notation in space-time (Part 1)
This is sort of a continuation of this and this previous discussions.
In the first of my links one sees the surjective isometry between real or complex $(1,3)$ signature Minkowski space and the real ...
1
vote
2answers
263 views
M-theory no lagrangian?
Is there any formulated lagrangian (density) for M-theory? If not, why is there no lagrangian?
If not, is this related to many vacua existing?
Thnx.
3
votes
1answer
217 views
Causality in String Theory
For a point particle we have light cone:
String Theory- with it's extended body concepts- however will not admit a light cone such as this. In particular the most problematic causal issue would be ...
5
votes
1answer
230 views
Bosonic Tachyon Condensation?
The tachyonic string mode in perturbative bosonic string theory indicates that the "vacuum", flat Minkowski $\mathbb{R}^{25,1}$, is not really a vacuum. What is conjectured about tachyon condensation ...
3
votes
1answer
169 views
What does AdS/CFT have to say about quantum gravity in our world?
The Ads side of the AdS/CFT correspondence is a model of quantum gravity in 5 dimensional antidesitter space. What can it say about quantum gravity in our 4-spacetime dimensions? Or is it just a toy ...
1
vote
1answer
111 views
1-Dimensional Sigma Models
I'm currently interested in 1-dimensional (linear) Sigma Models.
In the theory of 2-Dimensional GLSM, the fields can be viewed as an embedding of the worldsheet in some target Manifold of higher ...
5
votes
3answers
422 views
What is the physical significance of the dilaton in string theory?
Strings always have a dilaton in their spectrum. Its a scalar field (so presumably no spin), and so far a hypothetical particle. What is its physical significance?
5
votes
2answers
306 views
Is string length in string theory quantized?
Is there a minimal string length (maybe the Plank length?), and is it quantized?
Do strings have a 0-dimensional (ie point) cross-section?
4
votes
5answers
1k views
What differs string theory from philosophy or religion? [duplicate]
Possible Duplicate:
What experiment would disprove string theory?
A hypothesis without hard evidence sounds very much like philosophy or religion to me. All of them tries to establish a ...
1
vote
2answers
156 views
What exactly are right movers and left movers in string theory?
In string theory , What exactly are right movers and left movers ?Are they waves propagating along the string to the right and to the left respectively ?
Can some-one please show me how to derive in ...
1
vote
1answer
210 views
Has the use of the holographic principle of string theory in condensed matter physics silenced the skeptics?
It seems to me that the use of string theory in calculations of strongly-interacting matter in condensed matter physics is an example of the theory being on the right track. And then there's the ...
5
votes
4answers
413 views
Is String Theory a Field Theory?
Is String Theory a Field or Quantum Mechanical Theory of the String rather than a Particle?
I should know this having studied this for a term, but we jumped into the deep end, without really ...
3
votes
2answers
491 views
How does String Theory predict Gravity?
Firstly, General Relativity states that Spacetime is dynamic and is consonant with the distribution of matter/energy. How does String Theory predict gravity, when it is background dependent, that is ...
4
votes
0answers
164 views
The ${\cal N} = 3$ Chern-Simons matter lagrangian
This question is sort of a continuation of this previous question of mine.
I would like to know of some further details about the Lagrangian discussed in this paper in equation 2.8 (page 7) and in ...
5
votes
0answers
150 views
Why Brown York stress tensor == dual field theory's energy momentum tensor?
From the AdS/CFT dictionary, how to argue that the Brown York stress tensor for a gravity
system near the boundary is exactly the same as the energy momentum tensor of the dual field theory?
In the ...
6
votes
1answer
112 views
Who added $\frac{3}{2} \partial^2 c$ to the virasoro BRST current (and why)?
I've been looking at the literature on quantizing the bosonic string, and I noticed that there was a change made in the definition of the BRST current around 1992. However, I haven't found any ...
0
votes
1answer
89 views
Entropy, Mass and Brane gravity
Does string theory state as vibrational entropy increases, mass increases?
Related: What is a D-brane?
Reference: Cambridge Relativity
3
votes
0answers
146 views
Some more questions on conformal spinors of $SO(n,2)$
This is somewhat of a continuation of my previous question.
I had stated there that a conformal spinor ($V$) of $SO(n,2)$ can be created by taking a direct sum of two $SO(n-1,1)$ spinors $Q$ and $S$ ...
6
votes
1answer
146 views
If a fundamental theory exibits e.g. a mirror symmetry, in what sense it the underlying geometry real?
Are the more recently discovered symmetries in string theory such that the theories based on mirroring geometries are absolutely the same from an observable point of view?
I have mirror symmetry ...
3
votes
0answers
60 views
Relating the deformation of Calabi-Yau metrics and the conformal quantum field theories
(v2)
As I read e.g. in this question, the nice holonomy group features of Calabi-Yau manifolds are valuable regarding supersymmetry (I suspect because it's a symmetry involving the target manifold, ...
4
votes
2answers
346 views
The multiverse of eternal inflation
I don't have a clear picture of what is "by definition" the multiverse appearing in the models of eternal inflation. A long time ago I heard that it is a quantum state, but in the cosmology books I ...
0
votes
0answers
66 views
Does quantum field theory accept gravitational wave?
Does quantum field theory accept gravitational wave? As quantum field theory is flat spacetime theory, I wonder whether gravitational wave would be true.
Does contemporary string theory variants ...
0
votes
0answers
26 views
Query on dimensions [duplicate]
Possible Duplicate:
Measuring extra-dimensions
I have heard of dimensions as far as 8 dimensions in the world . Knowing that man can see or feel only 3 dimensions I want to know what are ...
3
votes
1answer
164 views
Lorentz spinors of $SO(n,1)$ and conformal spinors of $SO(n,2)$
It would be great if someone can give me a reference (short enough!) which explains the (spinor) representation theory of the groups $SO(n,1)$ and $SO(n,2)$.
I have searched through a few standard ...
-4
votes
1answer
205 views
What do scientists believe about existence in dimensions? [closed]
I couldn't really think of a suitable question title, I'm not sure if it's completely related or not.
But this is as far as I know (well, I thought it all up last night and it seemed extremely ...
9
votes
3answers
439 views
Is there any quantum-gravity theory that has flat space-time and gravitons?
Many quantum-gravity theories are strongly interacting. It is not clear
if they produce the gravity as we know it at low energies. So I wonder, is there
any quantum-gravity theory that
a) is a well ...
6
votes
2answers
391 views
Introduction to string theory
I am in the last year of MSc. and would like to read string theory. I have the Zwiebach Book, but along with it what other advanced book can be followed, which can be a complimentary to Zwiebach. I ...
9
votes
2answers
540 views
Does string theory have a notion of vacuum?
Does string theory have a notion of vacuum? If yes, what is known about it?
2
votes
0answers
129 views
What are the topics of string theory that are comprehensible with only a mathematical background on Manifolds and Algebraic Topology?
What are the topics of string theory that are comprehensible with only a mathematical background on manifolds and algebraic topology? Also, I have read only the first four chapters in Peskin & ...
1
vote
0answers
140 views
Derivation of the supergravity action in 11D
The Einstein-Hilbert action of general relativity is uniquely determined by general covariance and the requirement that only second derivatives in the metric appear. Yang-Mills theory can be motivated ...
4
votes
0answers
85 views
Calabi Yau compactification based on U(1) charges
In Green-Schwarz-Witten Volume 2, chapter 15, it is argued (roughly) that we need 6-dimensional manifolds of $SU(3)$ holonomy in order to receive 1 covariantly constant spinor field. And it turns out ...
3
votes
1answer
105 views
Supergroup action on $AdS_5XS^5$
In the context of the AdS/CFT correspondence I was trying to understand how the symmetry group of the underlying space $AdS_5 X S^5$ comes out to be the supergroup $SU(2,2|4)$. I can see how the ...
2
votes
0answers
81 views
Non-locality from quantum loops
I am reading a paper on quantum gravity (written circa 1988 but I don't think it's relevant to give a more precise reference) where I read the following statement: "universe loops will in general ...
6
votes
1answer
200 views
Reference for the ${\cal N}=3$ Chern-Simons Lagrangian at general $N_c$, $N_f$
I was wondering if someone could give me a reference where someone has explicitly written the Lagrangian for ${\cal N}=3$ $SU(N_c)$ Chern-Simons theory coupled to $N_f$ fundamental hypermultiplets.
...
4
votes
0answers
67 views
Defects in 3+1 TFTs/2+1 CFTs
I would like to know of good pedagogic references to learn about the notion of "defects" in TFTs and CFTs. I am specially interested in 3+1 TFTs (.and probably about their relation to 2+1 CFTs..)
In ...
