A class of theories that attempt to explain all existing particles (including force carriers) as vibrational modes of one-dimensional objects.
12
votes
0answers
203 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 ...
10
votes
0answers
278 views
A dictionary of string - standard physics correspondences
Motivated by the (for me very useful) remark
''Standard model generations in string theory are the Euler number of
the Calabi Yau, and it is actually reasonably doable to get 4,6,8, or 3
...
9
votes
0answers
213 views
Derivation of KLT relations
The KLT relations (Kawai, Lewellen, Tye) relate a closed string amplitude to a product of open ones. While I get the physics behind this I don't really understand the derivation in the original paper ...
8
votes
0answers
121 views
Compactifying on a circle and the exchange of R and NS sectors
I've noticed a general phenomenon in compactifying on a circle where if you start with, say, an NS field, then the KK fields with an index along the circle will be in the R sector, and those without ...
8
votes
0answers
121 views
Intuitive sketch of the correspondence of a string theory to its limiting quantum field theory
I'm looking for an intuitive sketch of how one shows the correspondence of string theory to a certain QFT. My best guess is that one calculates the scattering amplitudes in the string theory as a ...
8
votes
0answers
36 views
Minimal strings and topological strings
In http://arxiv.org/abs/hep-th/0206255 Dijkgraaf and Vafa showed that the closed string partition function of the topological B-model on a Calabi-Yau of the form $uv-H(x,y)=0$ coincides with the free ...
8
votes
0answers
48 views
Super Lie-infinity algebra of closed superstring field theory?
Bosonic closed string field theory is famously governed by a Lie n-algebra for $n = \infty$ whose $k$-ary bracket is given by the genus-0 (k+1)-point function in the BRST complex of the string.
One ...
7
votes
0answers
352 views
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 ...
7
votes
0answers
86 views
gauss-bonnet gravity constraints from string theory
recently there has been advances in observational constraints of gravity theories that contains scalars coupled to the gauss-bonnet topological term:
http://arxiv.org/abs/0704.0175
...
7
votes
0answers
53 views
Quantum statistics of branes
Quantum statistics of particles (bosons, fermions, anyons) arises due to the possible topologies of curves in D-dimensional spacetime winding around each other
What happens if we replace particles by ...
6
votes
0answers
94 views
Is it believed that all UV completions have “Maldacena duals”?
I have heard occasional rumors that effective field theories have gravity duals. For example, I've been told that UV momentum cutoffs in N=4 SYM become finite radii in AdS. I've heard speculations ...
6
votes
0answers
46 views
Pohlmeyer reduction of string theory for flat and AdS spaces
The definition of Pohlmeyer invariants in flat-space (as per eq-2.16 in Urs Schreiber's DDF and Pohlmeyer invariants of (super)string) is the following:
$ Z^{\mu_1...\mu_N} (\mathcal{P}) = ...
6
votes
0answers
49 views
String landscape in different dimensions
For D = 11 large (uncompactified) spacetime dimensions, the only "string theory" vacuum is M-theory
For D = 10, there are 5 vacua. Or maybe it's more correct to say 4, since type I is S-dual to ...
5
votes
0answers
57 views
Why do we identify symmetric 2nd rank tensors with spin-2 particles in string theory?
I am going through Tong's lecture notes on String Theory and came across the following irrep decomposition (Chap 2, p.43) of the bosonic string first excited states:
$$\text{traceless symmetric} ...
5
votes
0answers
101 views
Has hep-th/0312070 forgotten to fix $s_{0} = 1/2$ for the fermionic states in the second table on page 52?
Link to the original paper: The Gauge/String Correspondence Towards Realistic Gauge Theories (arXiv paper)
On page 52 we see that, for a theory of Dp-branes placed at an orbifold (orbifold = ...
5
votes
0answers
113 views
Are QFT solitons expected to represent standard model particles? Or strings?
Is work on solitons in QFT's focused on finding solutions that could represent the fundamental particles of the Standard Model, or is the work focused on finding particles Beyond The Standard Model? ...
5
votes
0answers
94 views
Master Field Large N limit
I would like to ask a question about the so-called ''Master Field''. As far as I understand, this represents a classical configuration in the large n limit (saddle point solution) but there is no ...
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 ...
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 ...
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}$ ...
5
votes
0answers
149 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 ...
5
votes
0answers
41 views
Why Are Even and Odd Regge Trajectories Degenerate?
The Gribov-Froissart projection treats even angular momentum differently from odd angular momentum.
But in QCD, I believe that the odd trajectories interpolate the even trajectories--- the two ...
5
votes
0answers
140 views
Chiral fermions from torsion flux in M-theory?
Witten's 1981 paper "Search for a realistic Kaluza-Klein theory" is frequently cited for its observation that, in a compactification of d=11 supergravity on a manifold with SU(3) x SU(2) x U(1) ...
4
votes
0answers
58 views
Dimensional transmutation in Gross-Neveu vs others
Firstly I don't know how generic is dimensional transmutation and if it has any general model independent definition.
Is dimensional transmutation in Gross-Neveau somehow fundamentally different ...
4
votes
0answers
45 views
Animating the Bosonic String
I am interested in studying the classical solutions to the Bosonic string in flat 3+1 dim. spacetime by having them rendered a moving picture on a computer. This is partly for fun, and partly to ...
4
votes
0answers
130 views
Implications of Unruh-inertia to theories of gravity
If it turns out to be true that the galaxy rotation curves can be explained away by Unruh modes that become greater than the Hubble scale at accelerations around $10^{-10} m/s^2$ as proposed in here, ...
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 ...
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 ...
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 ...
4
votes
0answers
25 views
What is the state-of-the-art on spacelike singularities in string theory?
What lessons do we have from string theory regarding the fate of singularities in general relativity?
What happens to black hole singularities? What happens to cosmological singularities?
Which ...
4
votes
0answers
142 views
Is string theory over a time varying background a conformal field theory to all orders in perturbation theory?
When computing the first order perturbative corrections to string theory over a curved background, we find the background has to be Ricci-flat if the dilaton is constant and we have no fluxes. Such is ...
3
votes
0answers
96 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?
3
votes
0answers
66 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 ...
3
votes
0answers
50 views
Does the ensemble of effective Lagrangians in the String theory landscape mostly include gauge theories?
String theory false vacua can be described by effective Lagrangians at low energy. Is there generally a correspondence between these effective Lagrangians and SU(N) gauge theories? Or do the effective ...
3
votes
0answers
54 views
Expectation of 2-form field $B_{MN}$ in string theory
In the context of string theory, in particular when we're dealing with a low energy effective action, if we have an effective action of the form:
$$S_{eff} \sim S^{(0)} + \alpha S^{(1)} + (\alpha)^2 ...
3
votes
0answers
124 views
Inclusion of information about external particles to calculate scattering amplitudes
In this (schematic) equation to calculate the scattering amplitude A by integrating over all possible world sheets and lifetimes of the bound states
$$ A = \int\limits_{\rm{life time}} d\tau ...
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 ...
3
votes
0answers
258 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 ...
3
votes
0answers
116 views
Dual Resonance Model: Fermions
I am going through Ramond's 1971 paper Dual Theory for Free Fermions Phys Rev D3 10, 2415 where he first attempts to introduce fermions into the conventional dual resonance model.
I get the 'gist' of ...
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 $S$ ...
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, ...
3
votes
0answers
130 views
Central charge at the fixed point of the ${\cal N}=2$ Landau-Ginzburg theory in $1+1$ dimensions
Let me first believe that the ${\cal N}=2$ Landau-Ginzburg theory does in the IR flow to a non-trivial fixed point and that if the potential is of the form $\Phi ^k$ then the central charge of the CFT ...
3
votes
0answers
71 views
Pohlmeyer reduction of string theory for flat- and AdS- spaces
The definition of Pohlmeyer invariants in flat-space (as per eq-2.16 in Urs Schreiber's DDF and Pohlmeyer invariants of (super)string) is the following:
$ Z^{\mu_1...\mu_N} (\mathcal{P}) = ...
3
votes
0answers
208 views
The implications of the holographic principle on string theory S-matrices
The S-matrix of superstring theory will have finitely many massive particles which decouple in the asymptotic future/past and massless particles like gravitons, photons and dilatons. Typically, there ...
3
votes
0answers
178 views
If D-branes are the same as p-branes, and p-branes open out to “another universe”, why is the other universe invisible in D-branes?
Related to my other misguided question, D-branes are equivalent to p-branes. D-branes are described by a sheet in topologically trivial spacetime. p-branes are extremal black branes. They have an ...
2
votes
0answers
50 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
50 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 - ...
2
votes
0answers
40 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 ...
2
votes
0answers
28 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
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 ...
