We relate a free scalar field in the Minkowski spacetime with a scalar field with a certain scaling dimension on a sphere of codimension two. This is realised by first performing a Radon transform of the “bulk” field on the Minkowski space to a field on a hyperplane identified with a de Sitter or Euclidean anti-de Sitter slice. The Radon transform is identified in turn with a scalar field obtained from a sphere of one further lower dimension through the so-called bulk reconstruction programme. We write down the Mellin modes of the bulk field as generalised hypergeometric functions using the Lee-Pomeransky method developed for evaluation of Feynman loop diagrams.

India

Samrat Bhowmick

Koushik Ray

Minkowski space holography and Radon transform

Bulk reconstruction formulas similar to HKLL are obtained for de Sitter and anti-de Sitter spaces as the inverse Gel'fand Graev Radon transform. While these generalize our previous result on the Euclidean anti-de Sitter space, their validity in here is restricted only to odd dimensions in both instances. The exact Wightman function for the de Sitter space is then derived. The GGR transform fixes the coefficient of the Wightman function. For the anti-de Sitter space it is shown that a reconstruction formula exists for the case of timelike boundary as well. The restriction on the domain of integration on the boundary is derived. As a special case, we point out that the formula is valid for the BTZ black hole as well.

Ireland

Siddhartha Sen

Holography in de Sitter and anti-de Sitter spaces and Gel'fand Graev Radon transform

We define Radon transform and its inverse on the two-dimensional anti-de Sitter space over local fields using a novel construction through a quadratic equation over the local field. We show that the holographic bulk reconstruction of quantum fields in this space can be formulated as the inverse Radon transform, generalizing the case over the reals, studied earlier.

Holography on local fields via Radon transform

The bulk reconstruction formula for a Euclidean anti-de Sitter space is directly related to the inverse of the Gel’fand-Graev-Radon transform. Correlation functions of a conformal scalar field theory in the boundary are thereby related to correlation functions of a self-interacting scalar field theory in the bulk at different loop orders.

Bulk reconstruction in AdS and Gel’fand-Graev-Radon transform

Using AdS/CFT prescription, we compute two point Yang-Mills correlator on a constant time slice for the Kasner background. Pushing the surface close to the initial singularity, we find, in some cases, the correlator does not develop pole. We further numerically calculate similar correlator where the bulk is a Kasner AdS soliton. We find that the qualitative behaviour of the correlator remains unchanged.