Four-dimensional quantum gravity in the conformal sector

Antoniadis, Ignatios; Mottola, Emil

doi:10.1103/physrevd.45.2013

Cited by 285 publications

(538 citation statements)

References 43 publications

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“…logarithmically with distance, and is therefore marginally relevant in the infrared with respect to the usual classical flat space fixed point [10]. The fluctuations generated by S anom also define a non-perturbative Gaussian infrared fixed point, with conformal field theory anomalous dimensions analogous to the two dimensional case [22]. This is possible only because new low energy degrees of freedom are contained in S anom which can fluctuate independently of the local metric degrees of freedom in S EH .…”

Section: Effective Action and Stress Tensor In Four Dimensionsmentioning

confidence: 99%

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Macroscopic effects of the quantum trace anomaly

2006

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The low energy effective action of gravity in any even dimension generally acquires non-local terms associated with the trace anomaly, generated by the quantum fluctuations of massless fields. The local auxiliary field description of this effective action in four dimensions requires two additional scalar fields, not contained in classical general relativity, which remain relevant at macroscopic distance scales. The auxiliary scalar fields depend upon boundary conditions for their complete specification, and therefore carry global information about the geometry and macroscopic quantum state of the gravitational field.The scalar potentials also provide coordinate invariant order parameters describing the conformal behavior and divergences of the stress tensor on event horizons. We compute the stress tensor due to the anomaly in terms of its auxiliary scalar potentials in a number of concrete examples, including the Rindler wedge, the Schwarzschild geometry, and de Sitter spacetime. In all of these cases, a small number of classical order parameters completely determine the divergent behaviors allowed on the horizon, and yield qualitatively correct global approximations to the renormalized expectation value of the quantum stress tensor.

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Section: Effective Action and Stress Tensor In Four Dimensionsmentioning

confidence: 99%

“…The fourth order differential operator appearing in this expression is [10,21,22] 8) which is the unique fourth order scalar operator that is conformally covariant, viz.…”

Section: Effective Action and Stress Tensor In Four Dimensionsmentioning

confidence: 99%

Macroscopic effects of the quantum trace anomaly

2006

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“…This option cannot be ruled out by the analysis of the present data [17,18]. In case that the new generation of cosmic observational experiments will indeed detect a variable DE, the natural question to ask is: would this fact really mean the manifestation of a qualitatively new physical reality such as quintessence [19], Chaplygin gas [20], extra dimensions [21] or of low-energy quantum gravity [22,23,24,25]? Let us emphasize here that one cannot honestly address this question without also exploring the possibility of a time-variable CC whose running is due to known physical effects, that is, due to the quantum effects of matter fields on a curved classical background [26].…”

Section: Introductionmentioning

confidence: 97%

Density perturbations for a running cosmological constant

Fabris

Shapiro

Solà

2007

J. Cosmol. Astropart. Phys.

152

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The dynamics of density and metric perturbations is investigated for the previously developed model where the decay of the vacuum energy into matter (or vice versa) is due to the renormalization group (RG) running of the cosmological constant (CC) term. The evolution of the CC depends on the single parameter ν, which characterizes the running of the CC produced by the quantum effects of matter fields of the unknown high energy theory below the Planck scale. The sign of ν indicates whether bosons or fermions dominate in the running. The spectrum of perturbations is computed assuming an adiabatic regime and an isotropic stress tensor. Moreover, the perturbations of the CC term are generated from the simplest covariant form suggested by the RG model under consideration. The corresponding numerical analysis shows that for ν > 0 there is a depletion of the matter power spectrum at low scales (large wave numbers) as compared to the standard ΛCDM model, whereas for ν < 0 there is an excess of power at low scales. We find that the LSS data rule out the range |ν| > 10 −4 while the values |ν| ≤ 10 −6 look perfectly acceptable. For ν < 0 the excess of power at low scales grows rapidly and the bound is more severe. From the particle physics viewpoint, the values |ν| ≃ 10 −6 correspond to the "desert" in the mass spectrum above the GUT scale M X ∼ 10 16 GeV . Our results are consistent with those obtained in other dynamical models admitting an interaction between dark matter and dark energy. We find that the matter power spectrum analysis is a highly efficient method to discover a possible scale dependence of the vacuum energy.

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“…The relation between infrared divergences and stability and the relation to the non-unitary gauge theory was discussed in [12] on a qualitative level; see also a recent discussion of the Euclidean infrared problems [6] . The particle production , instabilities and back reaction have been discussed from the various points of view in the papers [14] , [16] , [15] and references therein. A runaway particle production was studied in an interesting paper [17] 2 The composition principle and the Unruh detector…”

Section: Introductionmentioning

confidence: 99%

De Sitter space and eternity

2008

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This paper explores infrared quantum effects in the de Sitter space. The notion of "eternal manifolds" is introduced and it is shown that in most cases the de Sitter space doesn't belong to this class. It is unstable under small perturbations which may cause a breakdown of the de Sitter symmetry. The de Sitter string sigma model is discussed. It is argued that the gauge theory at the complex coupling is dual to the matrix elements of vertex operators in the de Sitter space, taken between the Bunch -Davies vacuum and the "out" state without particles. The described infrared effects are likely to screen away the cosmological constant.

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Four-dimensional quantum gravity in the conformal sector

Cited by 285 publications

References 43 publications

Macroscopic effects of the quantum trace anomaly

Macroscopic effects of the quantum trace anomaly

Density perturbations for a running cosmological constant

De Sitter space and eternity

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