Can early dark energy be detected in non-linear structure?

Francis, Matthew J.; Lewis, Geraint F.; Linder, Eric V.

doi:10.1111/j.1365-2966.2008.14286.x

Cited by 45 publications

(60 citation statements)

References 38 publications

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“…Here we simulate different dark energy models and study their observational signatures. A small number of papers have used N-body simulations to test scalar field cosmologies [5,6,7,8,9]. Rather than explicitly solving for different potentials, it is standard practice to modify the Friedmann equation using a form for the dark energy equation of state, w(z).…”

Section: Introductionmentioning

confidence: 99%

How BAO measurements can fail to detect quintessence

Jennings¹,

Baugh²,

Angulo

et al. 2010

AIP Conference Proceedings

168

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Abstract.We model the nonlinear growth of cosmic structure in different dark energy models, using large volume N-body simulations. We consider a range of quintessence models which feature both rapidly and slowly varying dark energy equations of state, and compare the growth of structure to that in a universe with a cosmological constant. We use a four parameter equation of state for the dark energy which accurately reproduces the quintessence dynamics over a wide range of redshifts. The adoption of a quintessence model changes the expansion history of the universe, the form of the linear theory power spectrum and can alter key observables, such as the horizon scale and the distance to last scattering. The difference in structure formation can be explained to first order by the difference in growth factor at a given epoch; this scaling also accounts for the nonlinear growth at the 15% level. We find that quintessence models which feature late (z < 2), rapid transitions towards w = −1 in the equation of state, can have identical baryonic acoustic oscillation (BAO) peak positions to those in ΛCDM, despite being very different from ΛCDM both today and at high redshifts (z ∼ 1000). We find that a second class of models which feature non-negligible amounts of dark energy at early times cannot be distinguished from ΛCDM using measurements of the mass function or the BAO. These results highlight the need to accurately model quintessence dark energy in N-body simulations when testing cosmological probes of dynamical dark energy.

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“…Here we simulate different dark energy models and study their observational signatures. A small number of papers have used N-body simulations to test scalar field cosmologies [5,6,7,8,9]. Rather than explicitly solving for different potentials, it is standard practice to modify the Friedmann equation using a form for the dark energy equation of state, w(z).…”

Section: Introductionmentioning

confidence: 99%

How BAO measurements can fail to detect quintessence

Jennings¹,

Baugh²,

Angulo

et al. 2010

AIP Conference Proceedings

168

View full text Add to dashboard Cite

show abstract

“…Here we simulate different dark energy models and study their observational signatures. A small number of papers have used N-body simulations to test scalar field cosmologies by modifying the expansion history alone (Ma et al, 1999;Linder & Jenkins, 2003;Klypin et al, 2003;Francis et al, 2008;Grossi & Springel, 2009;?). In Chapter 3 we carried out the most realistic simulations of quintessence dark energy to date, using an accurate parametrization for the quintessence models equation of state and a consistent linear theory power spectrum and appropriate cosmological parameters (so that the various models match the CMB, BAO and SN constraints).…”

Section: Discussionmentioning

confidence: 99%

“…As a result, a quintessence model with a varying equation The growth factor in each case has been normalised to unity today. been shown that models with a larger density of dark energy at high redshift than ΛCDM have more developed large scale structure at early times, when normalised to the same σ 8 today (Grossi & Springel, 2009;Francis et al, 2008).…”

Section: The Expected Impact Of Dark Energy On Structure Formationmentioning

confidence: 99%

“…The INV2 model was not included in this set of simulations as there is a negligible difference in the linear theory power spectrum from ΛCDM. Note Francis et al (2008) also generate the linear theory power spectrum for 'early dark energy' models and normalise all P(k) to have the same σ 8 today. Francis et al (2008) make an equivalent plot to Fig.…”

Section: Stage Ii: Use Of a Self-consistent Linear Theory P(k)mentioning

confidence: 99%

“…Note Francis et al (2008) also generate the linear theory power spectrum for 'early dark energy' models and normalise all P(k) to have the same σ 8 today. Francis et al (2008) make an equivalent plot to Fig. 3.11 but find a decrease in this ratio with decreasing scale (k > 0.2hMpc −1 ), using the parametrization for early dark energy proposed by Doran & Robbers (2006), in contrast to the ratio of unity we find on shows the P(k) ratio from the simulation for the quintessence models using the best fit parameters in Table A.3 (Stage III).…”

Section: Stage Ii: Use Of a Self-consistent Linear Theory P(k)mentioning

confidence: 99%

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Simulations of Dark Energy Cosmologies

Jennings

2012

Springer Theses

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source• a link is made to the metadata record in Durham E-Theses• the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. No part of this thesis has been submitted elsewhere for any other degree or qualification.The work of others has been duly acknowledged.The copyright of this thesis rests with the author. No quotations from it should be published without the author's prior written consent and information derived from it should be acknowledged. AbstractFuture galaxy redshift surveys will make high precision measurements of the cosmic expansion history and the growth of structure which will potentially allow us to distinguish between different scenarios for the accelerating expansion of the Universe. In this thesis we study the nonlinear growth of cosmic structure in different dark energy models, using ultra-large volume N-body simulations. We measure key observables such as the growth of large scale structure, the halo mass function and baryonic acoustic oscillations.We study the power spectrum in redshift space in ΛCDM and quintessence dark energy models and test predictions for the form of the redshift space distortions. An improved model for the redshift space power spectrum, including the non-linear velocity divergence power spectrum, is presented. We have found a density-velocity relation which is cosmology independent and which relates the non-linear velocity divergence spectrum to the non-linear matter power spectrum. We provide a formula which generates the non-linear velocity divergence P(k) at any redshift, using only the non-linear matter power spectrum and the linear growth factor at the desired redshift. We also demonstrate for the first time that competing cosmological models with identical expansion histories -one with a scalar field and the other with a time-dependent change to Newton's gravitational constant -can indeed be distinguished by a measurement of the rate at which structures grow.Our calculations show that linear theory models for the power spectrum in redshift space fail to recover the correct growth rate on surprisingly large scales, leading to catastrophic systematic errors. Improved theoretical models, which have been calibrated against simulations, are needed to exploit the exquisitely accurate clustering measurements expected from future surveys.

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Simulations of Quintessential Cold Dark Matter

Jennings

2012

Simulations of Dark Energy Cosmologies

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Can early dark energy be detected in non-linear structure?

Cited by 45 publications

References 38 publications

How BAO measurements can fail to detect quintessence

How BAO measurements can fail to detect quintessence

Simulations of Dark Energy Cosmologies

Simulations of Quintessential Cold Dark Matter

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