EU2 - Quantum Fields |
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Speaker |
Garcia-Saenz, Sebastian |
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Coauthors |
Renaux-Petel, Sebastien; Ronayne, John; Tada, Yuichiro |
| Talk Title |
Sidetracked Inflation, Orthogonal Non-Gaussianity, and Hyperbolic Field Space |
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Abstract |
Heavy scalar fields can undergo an instability during inflation as a result of their coupling to the inflaton’s kinetic term. This is known as the geometrical destabilization of inflation, as it relies on the negative curvature of the internal field space overcoming the stabilizing force of the potential. Under some assumptions, this instability can drive the system away from its original path in field space into a new inflationary phase, a scenario that we dub "sidetracked inflation". In this talk I will discuss the physical consequences of this second phase of inflation for several two-field nonlinear sigma models, starting with a general description of the background dynamics and explaining how it differs from the standard slow-roll scenarios. I will next describe our results for the cosmological parameters related to the power spectrum and non-Gaussianity, showing that the effects of the destabilized heavy field can be very significant, leading to important modifications in the observable predictions relative to the single-field expectations. In particular, in the case of a hyperbolic field space, this picture of inflation can give rise to large non-Gaussianities characterized by orthogonal shapes in an unusually generic way. |
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