nLab flat space holography




What is called flat space holography is a – somewhat more hypothetical – generalization of the holographic principle in the form of the AdS-CFT correspondence, which should be applicable not to the usual bulk spacetimes that are asymptotically anti de Sitter, but to bulks that are asymptotically Minkowskian.

In order to still relate this to branes notice that the far horizon geometry of all BPS branes is a flat orbifold spacetime (see there), but that “far” is Planck scale for single branes (“cone branes”), hence in the large 1/N limit (opposite to the large N limit in which the AdS-CFT correspondence applies).

In one more well-developed version of flat space holography, scattering amplitudes in asymptotically flat spacetimes are related to conformal field theories on celestial spheres in two dimensions lower – “celestial amplitudes”. This goes back to an observation in de Boer & Solodukhin 2003.



Early comments:

  • Edward Witten, Baryons and Branes in Anti de Sitter Space talk at Strings98 (1998) [web]

    (by the title, apparently originally intended to touch on AdS-QCD, but de facto ending with focus on the problem of flat space holography)

Dedicayed introduction and survey:


Original articles:

For JT-gravity/SYK model-duality (i.e. analogous to AdS2/CFT1 duality):

Celestial amplitudes and celestial holography

Introduction and survey:

Original articles:


  • Charlotte Sleight, Massimo Taronna, Celestial Holography Revisited (arXiv:2301.01810)

Description in terms of topological strings on twistor space:

See also:


Last revised on May 1, 2024 at 05:45:03. See the history of this page for a list of all contributions to it.