Can non-minimal coupling restore the consistency condition in bouncing universes?

Abstract

An important property of the three-point functions generated in the early universe is the so-called consistency condition. According to the condition, in the squeezed limit wherein the wavenumber of one of the three modes (constituting the triangular configuration of wavevectors) is much smaller than the other two, the three-point functions can be completely expressed in terms of the two-point functions. It is found that, while the consistency condition is mostly satisfied by the primordial perturbations generated in the inflationary scenario, it is often violated in the bouncing models. The validity of the consistency condition in the context of inflation can be attributed to the fact that the amplitude of the scalar and tensor perturbations freeze on super-Hubble scales. Whereas, in the bouncing scenarios, the amplitude of the scalar and tensor perturbations often grow rapidly as one approaches the bounce, leading to a violation of the condition. In this work, with the help of a specific example involving the tensor perturbations, we explicitly show that suitable non-minimal couplings can restore the consistency condition even in the bouncing models. We briefly discuss the implications of the result.

10 pages, 4 figures

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• Obviating PBH overproduction for SIGWs generated by Pulsar Timing Arrays in loop corrected EFT of bounce
• Perturbative unitarity and NEC violation in genesis cosmology
• Parity-violation in bouncing cosmology
• Regularized-Renormalized-Resummed loop corrected power spectrum of non-singular bounce with Primordial Black Hole formation
• Bouncing with shear: Implications from quantum cosmology
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• Stability of a viable non-minimal bounce
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• Universe bouncing its way to inflation
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• Gravitational Waves from Primordial Black Holes formed by Null Energy Condition Violation during Inflation
• Bouncing Cosmologies in modified gravity with space time torsion