A dynamical scalar field represents the simplest generalization of a pure Cosmological Constant as a candidate to explain the recent evidence in favour of the accelerated cosmic expansion. We review the dynamical properties of such a component, and argue that, even if the background expectation value of this field is fixed and the equation of state is the same as a Cosmological Constant, scalar field fluctuations can still be used to distinguish the two components. We compare predicted spectra of Cosmic Microvave Background (CMB) anisotropies in tracking scalar field cosmologies with the present CMB data, in order to get constraints on the amount and equation of state of dark energy. High precision experiments like SNAP, Planck and SNFactory, together with the data on Large Scale Structure, are needed to probe this issue with the necessary accuracy. Here we show the intriguing result that, with a strong prior on the value of the Hubble constant today, the assumption of a flat universe, and consistency relations between amplitude and spectral index of primordial gravitational waves, the present CMB data at 1σ give indication of a dark energy equation of state larger than −1, while the ordinary Cosmological Constant is recovered at 2σ.

Scalar field dark energy and cosmic microwave background / Baccigalupi, C.; Balbi, A.; Matarrese, S.; Perrotta, F.; Vittorio, N.. - In: NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS. - ISSN 0920-5632. - 124:(2003), pp. 68-71. [10.1016/S0920-5632(03)02079-6]

Scalar field dark energy and cosmic microwave background

Baccigalupi, C.;Perrotta, F.;
2003-01-01

Abstract

A dynamical scalar field represents the simplest generalization of a pure Cosmological Constant as a candidate to explain the recent evidence in favour of the accelerated cosmic expansion. We review the dynamical properties of such a component, and argue that, even if the background expectation value of this field is fixed and the equation of state is the same as a Cosmological Constant, scalar field fluctuations can still be used to distinguish the two components. We compare predicted spectra of Cosmic Microvave Background (CMB) anisotropies in tracking scalar field cosmologies with the present CMB data, in order to get constraints on the amount and equation of state of dark energy. High precision experiments like SNAP, Planck and SNFactory, together with the data on Large Scale Structure, are needed to probe this issue with the necessary accuracy. Here we show the intriguing result that, with a strong prior on the value of the Hubble constant today, the assumption of a flat universe, and consistency relations between amplitude and spectral index of primordial gravitational waves, the present CMB data at 1σ give indication of a dark energy equation of state larger than −1, while the ordinary Cosmological Constant is recovered at 2σ.
2003
124
68
71
https://arxiv.org/abs/astro-ph/0205217
Baccigalupi, C.; Balbi, A.; Matarrese, S.; Perrotta, F.; Vittorio, N.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/11782
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 4
  • ???jsp.display-item.citation.isi??? 4
social impact