91 research outputs found

    Resolving the Inflationary Power Spectrum

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    Recently there have been differing viewpoints on how to evaluate the curvature power spectrum generated during inflation. In a series of papers by some authors it has been argued that the renormalization scheme adopted for the inflaton field phi(x) to make finite should also be applied to |phi_k|^2. But this then modifies the curvature power spectrum in a non-trivial way. On the other hand, others have criticized this approach and suggested alternatives, which have been further countered by the original authors. We discuss these differing viewpoints and indicate inconsistencies in both approaches. We then resolve the issue by showing why the standard expression, without any non-trivial regularization, is still valid.Comment: To appear in the proceedings of The 10th International Symposium on Cosmology and Particle Astrophysics (CosPA2013

    Current Status of Warm Inflation

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    Warm inflation is an inflationary scenario in which a thermal bath coexists with the inflaton during inflation. This is unlike standard cold inflation in which the Universe is effectively devoid of particles during inflation. The thermal bath in warm inflation is maintained by the dissipation of the inflaton's energy through its couplings to other fields. Many models of warm inflation have been proposed and their predictions have been compared with cosmological data. Certain models of inflation that are disallowed in the context of cold inflation by the data are allowed in the warm inflationary scenario, and vice versa.Comment: 9 pages, 3 figures; Slightly longer version of a brief review talk at the 18th Lomonosov Conference on Elementary Particle Physics at Moscow State University, August 24-30, 201

    Studying Electroweak Baryogenesis using Evenisation and the Wigner Formalism

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    We derive the kinetic equation for fermions and antifermions interacting with a planar Higgs bubble wall during the electroweak phase transition using the `evenisation' procedure and the Wigner formalism for a Lagrangian with the phase of the complex fermion mass rotated away. We obtain the energy, velocity and force for the particles in the presence of the Higgs bubble wall. Our results using both methods are in agreement. This indicates the robustness of evenisation as a method to study quantum corrections to the velocity and force for particles in the Higgs wall during the electroweak phase transition. We also derive the transport equations from the zeroth and first moment of the kinetic equation.Comment: no figures (Error in indentification of antiparticle states corrected.

    Gravitino production in an inflationary Universe and implications for leptogenesis

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    Models of leptogenesis are constrained by the low reheat temperature at the end of reheating associated with the gravitino bound. However a detailed view of reheating, in which the maximum temperature during reheating, \Tmax, can be orders of magnitude higher than the reheat temperature, allows for the production of heavy Majorana neutrinos needed for leptogenesis. But then one must also consider the possibility of enhanced gravitino production in such scenarios. In this article we consider gravitino production during reheating, its dependence on \Tmax, and its relevance for leptogenesis. Earlier analytical studies of the gravitino abundance have only considered gravitino production in the post-reheating radiation dominated era. We find that the gravitino abundance generated during reheating is comparable to that generated after reheating. This lowers the upper bound on the reheat temperature by a factor of 4/3.Comment: Journal version, minor change in title, 13 pages (revtex), 2 eps figure

    The Angular Dependence of the Three-Point Correlation Function of the Cosmic Microwave Background Radiation as Predicted by Inflationary Cosmologies

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    Inflationary models predict a definite, model independent, angular dependence for the three-point correlation function of ΔT/T\Delta T/T at large angles (greater than 1\sim 1^\circ) which we calculate. The overall amplitude is model dependent and generically unobservably small, but may be large in some specific models. We compare our results with other models of nongaussian fluctuations.Comment: 7 pages, 3 figures (described but not included, available on request), in Plain Tex, UCSBTH-92-3
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