Ghost Inflation

By N. Arkani-Hamed, P. Creminelli, S. Mukohyama, M. Zaldarriaga. 2003

562 citations recorded by the source corpus.

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 ex-cluded 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 negligi-ble. 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.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/ccd3a3a395c8be5a0c1a57d5efbce5bb27d3408d

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Citations in the corpus

Planck 2015 results. XVII. Constraints on primordial non-Gaussianity (2015, unknown): “(4) Equilateral and orthogonal shapes emerge also in models characterized by more general higher-derivative interactions, such as ghost inflation (Arkani-Hamed et al. 2004), effective field theories of inflation (Cheung et al. 2008; Senatore et al. 2010; Bartolo et al. 2010a), or the so…”
The Effective Field Theory of Inflation (2007, background): “This implies that the spatial kinetic term for the Goldstone vanishes, as we will see in the discussion of Ghost Inflation.”
The phase transition to eternal inflation (2008, methodology): “The same conclusion holds in another interesting case of single field inflation: that of ghost inflation [23, 24].”
Ghost condensation and a consistent infrared modification of gravity (2003, background): “It is also possible that M is much larger; this could be the remnant of ghost condensation triggering an earlier de Sitter epoch in the universe, to drive inflation [17].”
COrE (Cosmic Origins Explorer) A White Paper (2011, background): “, DBI [89] and ghost inflation [90]) generate ‘equilateral’ NG, while trans-Planckian effects generate NG which peaks for ‘folded/flattened’ triangles; inflationary models violating slow-roll can generate more complicated shapes (see, e.”
Solid Inflation (2012, background): “A similar mechanism is at work in ghost inflation [23], or in the EFT description of finite-temperature superfluids [24].”
Equilateral Non-Gaussianity and New Physics on the Horizon (2011, methodology): “This model is typically referred to as “ghost inflation” [22].”
Planck 2018 results. IX. Constraints on primordial non-Gaussianity (2019, methodology): “Nevertheless, we shall also explicitly search for such EFT shapes, analysing their exact non-separable predicted shapes, BEFT1 and BEFT2, along with those of DBI, BDBI, and ghost inflation, Bghost (Arkani-Hamed et al. 2004).”
Limits on non-Gaussianities from WMAP data (2005, background): “98 with the ghost inflation [8] prediction and (2)Eq.”
Galileon inflation (2010, background): “However, when large nonlinearities are associated with the self-interactions of π there exists a decoupling limit in which reliable predictions can be extracted while neglecting gravity [4, 43, 50, 51].”