Abstract

We propose a new scenario for early cosmology, where an inflationary de Sitter phase is obtained with a ghost condensate. The transition to radiation dominance is triggered by the ghost itself, without any slow-roll potential. Density perturbations are generated by fluctuations around the ghost condensate and can be reliably computed in the effective field theory. The fluctuations are scale invariant as a consequence of the de Sitter symmetries; however, the size of the perturbations are parametrically different from conventional slow-roll inflation, and the inflation happens at far lower energy scales. The model makes definite predictions that distinguish it from standard inflation, and can be sharply excluded or confirmed by experiments in the near future. The tilt in the scalar spectrum is predicted to vanish ( n s = 1), and the gravity wave signal is negligible. The non-Gaussianities in the spectrum are predicted to be observable: the 3-point function is determined up to an overall 𝒪(1) constant, and its magnitude is much bigger than in conventional inflation, with an equivalent f NL ≃100, not far from the present WMAP bounds.

Keywords

PhysicsCMB cold spotInflation (cosmology)Non-GaussianityDe Sitter universePrimordial fluctuationsCosmological perturbation theoryObservableSlow rollInflatonSpectral densityCosmic background radiationCosmologyScalar (mathematics)Cosmological constantMathematical physicsTheoretical physicsCosmic microwave backgroundQuantum mechanicsUniverse

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Year
2004
Type
article
Volume
2004
Issue
04
Pages
001-001
Citations
521
Access
Closed

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Cite This

Nima Arkani–Hamed, Paolo Creminelli, Shinji Mukohyama et al. (2004). Ghost inflation. Journal of Cosmology and Astroparticle Physics , 2004 (04) , 001-001. https://doi.org/10.1088/1475-7516/2004/04/001

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DOI
10.1088/1475-7516/2004/04/001