All Questions
51
questions
1
vote
0
answers
64
views
Reparameterization invariance in gravity
It's often said that gravity/general relativity has 'reparameterization invariance.' In particular, this comes up when people talk about the duality between the Sachdev-Ye-Kitaev (SYK) model and ...
- 2,504
4
votes
1
answer
253
views
Jackiw-Teitelboim (JT) gravity as a matrix integral
I am reading https://arxiv.org/abs/1903.11115 by Saad, Shenker and Stanford. They relate an (averaged) $n$-point function in a random double-scaled matrix model to a path integral genus expansion in ...
- 165
2
votes
1
answer
101
views
Notion of mass of a quantum field theory in AdS space-time
Consider a scalar field theory in $AdS_{d+1}$ spacetime
\begin{equation}
S= -\frac{1}{2}\int d^{d+1} x \sqrt{-g} (\partial_\mu \phi \partial_\nu \phi g^{\nu \mu} + m^2 \phi^2 )
\end{equation}
On ...
- 469
1
vote
1
answer
309
views
Calculation of interaction of gravitational waves with a black hole
We have a well understood interacting electromagnetic system, an electromagnetic wave interacting with an atom. We use perturbation theory to calculate what happens in such a system. The result is of ...
- 251
1
vote
1
answer
140
views
AdS-CFT correspondance from 1D to 4D
From what I understand the AdS-CFT correspondence states that the bulk dynamics of a $n$-dimensional gravitational theory are encoded in the degrees of freedom of its dual CFT in the $(n-1)$ ...
- 153
6
votes
1
answer
200
views
Conformal blocks in AdS/CFT
In a CFT one can expand correlation functions in conformal blocks, for example the four-point function can be written (schematically) as:
$$\langle \mathcal{O}_1 (x_1) \mathcal{O}_2 (x_2) \mathcal{O}...
- 1,723
2
votes
0
answers
76
views
Non-factorization of partition functions in AdS/CFT
I have seen this comment a lot in recent papers. This has to do with the AdS/CFT correspondence and Euclidean asymptotically AdS wormholes.
So when we calculate the partition function of two $D-1$ ...
- 2,035
0
votes
1
answer
88
views
How AdS/CFT solves the non-renormalizability of gravity?
According to AdS/CFT, all gravity calculation in AdS can be mapped to CFT calculations on the boundary. Then what are the loop divergences in AdS gravity be mapped to the CFT side? Or put it ...
- 1
7
votes
1
answer
433
views
String theory in ${\rm AdS}_3$ and the ${\rm SL}{(2,\mathbb{R})}$ WZW model on the worldsheet
The WZW model on the sphere $S^2$ with group $G$ and level $k$ is described by the action for a $G$-valued field $g : S^2\to G$ (see these notes by Lorenz Eberhardt):
$$S[g]=\dfrac{1}{4\lambda^2}\int_{...
- 36.4k
1
vote
0
answers
54
views
Naked singularities in negative $M$ BTZ black hole geometry
Consider a BTZ black hole geometry,
\begin{equation}
ds^2=-N(r)^2dt^2+N(r)^{-2}dr^2+r^2(N^\phi dt+d\phi)^2,
\end{equation}
where $M>0$, $N(r)^2=-M+\frac{r^2}{l^2}+\frac{J}{4r^2}$ and $N^\phi(r)=-\...
- 699
4
votes
0
answers
116
views
Relation between bulk Hamiltonian in AdS and stress energy of CFT
Consider the following two situations:
One can define a stress energy for AdS which matches with the expectation value for the CFT stress tensor.
Consider bulk metric perturbations of the form:
$$g_{...
- 672
2
votes
0
answers
232
views
The black hole horizon of Jackiw-Teitelboim (JT) gravity
I am reading the papers about black hole in $AdS_2$, which can be regarded as a solution in JT gravity. More concretely I am reading this paper https://arxiv.org/abs/1908.08523 "Jackiw-Teitelboim ...
- 669
1
vote
0
answers
98
views
Dilaton background in Replica wormholes publication
Refering to the paper "Replica Wormholes and the Entropy of Hawking Radiation" by Almheiri et al. in arXiv:1991.12333. The authors consider Jackiw-Teitelboim gravity theory describing a ...
- 11
5
votes
2
answers
386
views
de-Sitter space as near-horizon limit of Black Holes
We know that we can obtain $AdS_{2}$ x $S_{2}$ spacetime as the near-horizon geometry of an extremal/ near extremal RN (or Kerr) Black Hole in asymptotically flat spacetime. It is also known that we ...
- 1,182
3
votes
0
answers
167
views
Conserved charges without conserved currents?
I recently read (Section 9.3 of J.Kaplan AdS/CFT notes) that we can have QFT's s.t. we have conserved charges but NO associated conserved currents. How is this related to the gauging of global ...
- 1,182