Quantum effects can render w < -1 on cosmological scales

By V. Onemli, Richard P. Woodard. 2004

361 citations recorded by the source corpus.

We report on a revision of our previous computation of the renormalized expectation value of the stress-energy tensor of a massless, minimally coupled scalar with a quartic self-interaction on a locally de Sitter background. This model is important because it demonstrates that quantum effects can lead to violations of the weak energy condition on cosmological scales--on average, not just in fluctuations--although the effect in this particular model is far too small to be observed. The revision consists of modifying the propagator so that dimensional regularization can be used when the dimension of the renormalized theory is not four. Although the finite part of the stress-energy tensor does not change (in D=4) from our previous result, the counterterms do. We also speculate that a certain, finite and separately conserved part of the stress tensor can be subsumed into a natural correction of the initial state from free Bunch-Davies vacuum.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/b7ae5274263bc75dcb2823552d01c3ee41d529b9

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Citations in the corpus

Two-loop scalar self-mass during inflation (2004, background): “As with the renormalized stress–energy tensor [3], we conjecture that the exponentially falling terms on the last line could be absorbed into a perturbative modification of the initial state.”
A kinematical approach to dark energy studies (2006, background): “…the dynamical (Ωm, w) plane, models with w < −1, known as ‘phantom’ dark energy models, violate the dominant energy condition (Carroll et al. 2003; Onemli & Woodard 2004) and present serious problems relating to the treatment of dark energy perturbations (Hu 2005; Vikman 2005; Caldwell &…”
Observational constraints on teleparallel dark energy (2011, background): “The first is to modify the content of the universe by introducing the dark energy sector, which can be based on a canonical scalar field (quintessence) [6–22], a phantom field [23–28], or on the combination of both these fields in a unified scenario called quintom [29–35] (see [36] for a review).”