Naturalness in cosmological initial conditions

F. Nitti, M. Porrati, J. W. Rombouts

    Research output: Contribution to journalArticle

    Abstract

    We propose a novel approach to the problem of constraining cosmological initial conditions. Within the framework of effective field theory, we classify initial conditions in terms of boundary terms added to the effective action describing the cosmological evolution below Planckian energies. These boundary terms can be thought of as spacelike branes which may support extra instantaneous degrees of freedom and extra operators. Interactions and renormalization of these boundary terms allow us to apply to the boundary terms the field-theoretical requirement of naturalness, i.e. stability under radiative corrections. We apply this requirement to slow-roll inflation with nonadiabatic initial conditions, and to cyclic cosmology. This allows us to define in a precise sense when some of these models are fine-tuned. We also describe how to parametrize in a model-independent way non-Gaussian initial conditions; we show that in some cases they are both potentially observable and pass our naturalness requirement.

    Original languageEnglish (US)
    Article number063503
    JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
    Volume72
    Issue number6
    DOIs
    StatePublished - Sep 15 2005

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    Initial conditions
    Term
    requirements
    Requirements
    Effective Field Theory
    Effective Action
    Cosmology
    Branes
    Renormalization
    Inflation
    cosmology
    Instantaneous
    degrees of freedom
    Degree of freedom
    Classify
    operators
    Operator
    Energy
    Interaction
    Model

    ASJC Scopus subject areas

    • Physics and Astronomy(all)
    • Nuclear and High Energy Physics
    • Mathematical Physics

    Cite this

    Naturalness in cosmological initial conditions. / Nitti, F.; Porrati, M.; Rombouts, J. W.

    In: Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol. 72, No. 6, 063503, 15.09.2005.

    Research output: Contribution to journalArticle

    Nitti, F. ; Porrati, M. ; Rombouts, J. W. / Naturalness in cosmological initial conditions. In: Physical Review D - Particles, Fields, Gravitation and Cosmology. 2005 ; Vol. 72, No. 6.
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