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IberiCos 2025

14–16 Apr 2025
Europe/Lisbon timezone

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Session

Session 6 - Early Universe

15 Apr 2025, 11:30
Auditorium C.1

Auditorium C.1

Department of Physics (University of Coimbra)

Conveners

Session 6 - Early Universe

  • Session convener: Richard Holman

Presentation materials

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  1. 4. Echoes of the Higgs: Gravitational Waves and the Fate of the Electroweak Vacuum
    Dr JAVIER RUBIO (Universidad Complutense de Madrid)
    15/04/2025, 11:30
    Talk

    We explore a minimal scenario where the Standard-Model Higgs is responsible for reheating the Universe after inflation and produces a significant background of gravitational waves. The characteristic features of such signal can be directly correlated to the classical stability of the electroweak vacuum, thus offering a novel connection between the inflationary scale and the top quark mass at...

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  2. 49. Current constraints on cosmological scenarios with very low reheating temperatures
    Nicola Barbieri (INFN Ferrara)
    15/04/2025, 11:45
    Talk

    If reheating occurs at sufficiently low temperatures (below $20$ MeV), neutrinos--assuming they are populated only through weak interactions--do not have enough time to reach thermal equilibrium before decoupling. We present an updated analysis of cosmological models with very low reheating scenarios, including a more precise computation of neutrino distribution functions, leveraging the...

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  3. 45. Testing inflationary models with de Sitter Swampland Conjectures
    Prof. Orfeu Bertolami (University of Porto)
    15/04/2025, 12:00
    Talk

    The de Sitter Swampland Conjectures are used to test some inflationary models compatible with CMBdata. We find that warm inflationary models, with one or more scalar fields, and the Claplygin-inspired models for some class of potentials satisfy the de Sitter Swampland Conjectures. Inflationary models in the context of theories of gravity that couple non-minimally curvature and matter are shown...

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  4. 34. Schwinger Current in de Sitter Space
    Paulo B. Ferraz (University of Coimbra)
    15/04/2025, 12:15
    Talk

    We study classical background electric fields and the Schwinger effect in de Sitter space. We show that having a constant electric field in de Sitter requires the photon to have a tachyonic mass proportional to the Hubble scale. This has physical implications for the induced Schwinger current which affect its IR behaviour. To study this we recompute the Schwinger current in de Sitter space for...

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  5. 23. Preheated inflation
    Diogo Gorgulho (University of Coimbra)
    15/04/2025, 12:30
    Talk

    We develop and analyse a novel mechanism based on Warm Little Inflaton models that allows for production of scalar particles $\chi$ during the slow-roll regime due to a narrow parametric resonance. We show that an appreciable energy density of $\chi$ particles can be generated through this mechanism without it becoming the dominant contribution to the Friedmann equation, thus preserving the...

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