All Questions
Tagged with quantum-anomalies string-theory
58
questions
8
votes
2
answers
3k
views
Weyl anomaly in 2d CFT (string theory lectures by D.Tong)
In his lectures on String Theory (http://www.damtp.cam.ac.uk/user/tong/string.html), Tong gives a proof of the Weyl anomaly, using equation $(4.37)$. It seems wrong to me.
Here he uses the OPE between ...
- 106
0
votes
1
answer
116
views
Proposal of the Virasoro modes and algebra
Hi I am wondering what the first published paper on Virasoro modes was? And what about Virasoro algebra?
- 93
4
votes
1
answer
1k
views
Why are critical dimensions and central charge linkable?
From wikipedia:
"In order for a string theory to be consistent, the worldsheet theory must be conformally invariant. The obstruction to conformal symmetry is known as the Weyl anomaly and is ...
2
votes
1
answer
701
views
Why must the conformal anomaly on string worldsheet be cancelled?
Viewing the coordinates of spacetime as fields on string worldsheet, the strings are described by the Polyakov action which presents conformal symmetry (including others) at the claasical level.
Now ...
- 3,691
1
vote
1
answer
137
views
How to derive an $E_8$ algebra?
What is the simplest way to derive an $E_8$ algebra? I am not interested in $E_8$ itself but what would compel one to think about it. I know for example why you would want to think about $SU(2)$ and ...
user151266
2
votes
0
answers
240
views
Faddeev-Popov-Determinant of Polyakov Path Integral
I'm currently trying to understand the paper "Quantum Geometry of bosonic Strings" by Polyakov. I think I roughly understand the X integration, but when it comes to the integration over the metric ...
- 21
5
votes
0
answers
232
views
Where does chiral matter at conical singularities "come from" in M-theory?
It seems to be accepted that to produce chiral fermionic matter in a compactification $\mathbb{R}^4\times X$ of M-theory/11d SUGRA to four dimensions, we need the seven-manifold $X$ to have isolated (...
- 126k
3
votes
1
answer
8k
views
Why are there specifically 10, 11, or 26 dimensions in string theory? [duplicate]
I know that current string theories state that there are 10, 11, or 26 spacetime dimensions in superstring theory, M-theory, and bosonic string theory, respectively. But when I looked up why those ...
5
votes
2
answers
571
views
Kaluza-Klein in superstring theory
In superstring theory, it says that they wrap 16 dimensions on a torus given by $\mathbb{R}^{16}$ divided by a SO(32) or $E_8 \times E_8$ lattice and this gives a gauge group of the same name.
But in ...
user84158
1
vote
0
answers
99
views
How to visualize a sphere bundle?
In the paper ``Gravitational Anomaly Cancellation for M Theory Fivebranes", the authors consider removing a tubular region of radius $\epsilon$ around the M5 brane (in order to make sense of the three ...
- 2,095
7
votes
1
answer
483
views
Target Space Lorentz Invariance vs. World Sheet Weyl Invariance
The Polyakov action, $S\sim \int d^2\sigma\sqrt{\gamma}\, \gamma_{ab}\partial^a X^\mu \partial ^b X_\mu$, has the well known classical symmetries of world sheet diffeomorphism invariance, world ...
- 3,492
1
vote
1
answer
268
views
Polyakov equation in the strings theory
In the equation of Polyakov there wouldn't be in our universe 10 or 11 dimensions but more (26) because it is referred to the bosonic theory. Are there any connections between this equation and the ...
- 43
1
vote
1
answer
122
views
What are the two dimensions of relativity that are added to string theory?
Based on the Ramanujam's modular functions, somehow these magic numbers 10 and 26 spacetime dimensions appear in string theory. The dimensions can be viewed as 8 + 2 and 24 + 2. The number 2 is added ...
- 13
10
votes
1
answer
671
views
Confusion about two definitions of anomalies
As I am currently studying for an exam about quantum field theory and string theory, I got confused about the notion of "anomalies" and how they are actually defined. Similar questions have already ...
- 7,309
4
votes
2
answers
1k
views
Traces in different representation
I am actually working with Green-Schwarz anomaly cancellation mechanism in which I have came across a strange formula which relates trace in the adjoint representation (Tr) to trace in fundamental ...
- 662