English

Projective Coordinates and Projective Space Limit

High Energy Physics - Theory 2008-11-26 v2

Abstract

The "projective lightcone limit" has been proposed as an alternative holographic dual of an AdS space. It is a new type of group contraction for a coset G/H preserving the isometry group G but changing H. In contrast to the usual group contraction, which changes G preserving the spacetime dimension, it reduces the dimensions of the spacetime on which G is realized. The obtained space is a projective space on which the isometry is realized as a linear fractional transformation. We generalize and apply this limiting procedure to the "Hopf reduction" and obtain (n-1)-dimensional complex projective space from (2n-1)-dimensional sphere preserving SU(n) symmetry.

Cite

@article{arxiv.0707.0326,
  title  = {Projective Coordinates and Projective Space Limit},
  author = {Machiko Hatsuda and Kiyoshi Kamimura},
  journal= {arXiv preprint arXiv:0707.0326},
  year   = {2008}
}

Comments

16 pages, v2: modified the section 2.1 clarifying the difference from IW contraction, added notes & references, version to appear in Nuclear Physics B

R2 v1 2026-06-21T08:54:33.755Z