A note on the semiclassicality of cosmological perturbations

Abstract

Moving from the consideration that matter fields must be treated in terms of their fundamental quantum counterparts, we show straightforward arguments, within the framework of ordinary quantum mechanics and quantum field theory, in order to convince readers that cosmological perturbations must be addressed in term of the semiclassical limit of the expectation value of quantum fields. We first take into account cosmological perturbations originated by a quantum scalar field, and then extend our treatment in order to account for the expectation values of bilinears of Dirac fermion fields. The latter can indeed transform as scalar quantities under diffeomorphisms, as well as all the other bilinear of the Dirac fields that belong to the Clifford algebra. This is the first of a series of works that is intended to prove that cosmological quantum perturbations can actually be accounted for in terms of Dirac fermion fields, which must be treated as fundamental quantum objects, and their dynamics.

17 pages

References in corpus (7)

• Dark Energy Model with Spinor Matter and Its Quintom Scenario
• The cosmological BCS mechanism and the Big Bang Singularity
• Fermi-bounce cosmology and the fermion curvaton mechanism
• Dynamics of Gauge Field Inflation
• Quantum gravity as a Fermi liquid
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Cited by in corpus (3)

• Bouncing cosmologies with dark matter and dark energy
• UV self-completion of a theory of Superfluid Dark Matter
• Dark matter and baryogenesis in the Fermi-bounce curvaton mechanism