Large non-Gaussianity in multiple-field inflation
- Institute for Theoretical Physics, Utrecht University, Postbus 80.195, 3508 TD Utrecht (Netherlands)
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)
We investigate non-Gaussianity in general multiple-field inflation using the formalism we developed in earlier papers. We use a perturbative expansion of the nonlinear equations to calculate the three-point correlator of the curvature perturbation analytically. We derive a general expression that involves only a time integral over background and linear perturbation quantities. We work out this expression explicitly for the two-field slow-roll case, and find that non-Gaussianity can be orders of magnitude larger than in the single-field case. In particular, the bispectrum divided by the square of the power spectrum can easily be of O(1-10), depending on the model. Our result also shows the explicit momentum dependence of the bispectrum. This conclusion of large non-Gaussianity is confirmed in a semianalytic investigation of a simple quadratic two-field model.
- OSTI ID:
- 20782893
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 73, Issue 8; Other Information: DOI: 10.1103/PhysRevD.73.083522; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
Similar Records
On the Issue of the {zeta} series convergence and loop corrections in the generation of observable primordial non-Gaussianity in slow-roll inflation. II. The trispectrum
Non-Gaussianity in two-field inflation beyond the slow-roll approximation