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Open access
Mar 25, 2014

Improvement of energy-momentum tensor and non-Gaussianities in holographic cosmology

Journal of High Energy Physics
  • Shinsuke Kawai
  • ,
  • Yu Nakayama

Volume
2014
Number
6
Language
Publishing type
Research paper (scientific journal)
DOI
10.1007/JHEP06(2014)052

In holographic models of cosmology based on the (A)dS/CFT correspondence,
conformal symmetry is implicit in the dual description of the Universe.
Generically, however, one cannot expect the (broken) conformal invariance in
the cosmic fluctuations as only the scale invariance is manifest in
experiments. Also, in order for the prediction of the holographic models to
make sense, the conformal symmetry needs to be broken as the scalar mode of the
metric fluctuations becomes pure gauge in the conformal limit. We discuss the
improvement ambiguity of the energy-momentum tensor in this context and
construct a holographic model of the Universe that preserves the scale
invariance but not necessarily the full conformal invariance. Our sample
computation using a weakly coupled dual field theory shows that the orthogonal
type of non-Gaussianity is present over and above the equilateral type. The
improvement ambiguity corresponds to the choice of the energy momentum tensor
that will couple to our particle physics sector after inflation. Our results
show that the holographic prediction of the cosmological parameters crucially
depends on such a choice.

Link information
DOI
https://doi.org/10.1007/JHEP06(2014)052
arXiv
http://arxiv.org/abs/arXiv:1403.6220
URL
http://arxiv.org/abs/1403.6220v1
URL
http://arxiv.org/pdf/1403.6220v1 Open access
Scopus
https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84904346454&origin=inward Open access
Scopus Citedby
https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=84904346454&origin=inward
ID information
  • DOI : 10.1007/JHEP06(2014)052
  • ISSN : 1126-6708
  • eISSN : 1029-8479
  • arXiv ID : arXiv:1403.6220
  • SCOPUS ID : 84904346454

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