Conformal invariant cosmological perturbations via the covariant approach

Abstract

It is known that some cosmological perturbations are conformal invariant. This facilitates the studies of perturbations within some gravitational theories alternative to general relativity, for example the scalar-tensor theory, because it is possible to do equivalent analysis in a certain frame in which the perturbation equations are simpler. In this paper we revisit the problem of conformal invariances of cosmological perturbations in terms of the covariant approach in which the perturbation variables have clear geometric and physical meanings. We show that with this approach the conformal invariant perturbations are easily identified.

9 pages, the version to appear in JCAP

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Cited by in corpus (5)

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• Reconstruction of extended inflationary potentials for attractors
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• The slow expansion with nonminimal derivative coupling and its conformal dual
• Conformal invariant cosmological perturbations via the covariant approach: multicomponent universe