A comparison of perturbations in fluid and scalar field models of dark energy

Abstract

We compare perturbations in a fluid model of dark energy with those in a scalar field. As compared to the $\Lambda$CDM model, large scale matter power spectrum is suppressed in fluid model as well as in a generic quintessence dark energy model.To check the efficacy of fluid description of dark energy in emulating a scalar field, we consider a potential which gives the same background evolution as a fluid with a constant equation of state. We show that for sub-Hubble scales, a fluid model effectively emulates a scalar field model. At larger scales, where dark energy perturbations may play a significant role, the fluid analogy breaks down and the evolution of matter density contrast depends on individual scalar field models.

arXiv commentRevtex, 4 pages, 3 postscript figures, minor revisions, figures modified, references added, Phys. Rev. D (in press)

References in corpus (44)

• Dynamics of dark energy
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• The Cosmological Constant and Dark Energy
• Cosmological Constant - the Weight of the Vacuum
• The Case for a Positive Cosmological Lambda-term
• The Supernova Legacy Survey: Measurement of Omega_M, Omega_Lambda and w from the First Year Data Set
• Dark Matter and Dark Energy
• Dark Energy and Gravity
• Probing dark energy perturbations: the dark energy equation of state and speed of sound as measured by WMAP
• Crossing the Phantom Divide: Dark Energy Internal Degrees of Freedom
• The shape of the SDSS DR5 galaxy power spectrum
• On the spherical collapse model in dark energy cosmologies
• Large Scale Cosmic Microwave Background Anisotropies and Dark Energy
• Density perturbations in an Universe dominated by the Chaplygin gas
• A measurement of Omega from the North American test flight of BOOMERANG
• Structure formation in the presence of dark energy perturbations
• A Low CMB Quadrupole from Dark Energy Isocurvature Perturbations
• Structure Formation in Inhomogeneous Dark Energy Models
• Dark Energy: the Cosmological Challenge of the Millennium
• Constraining Dark Energy Anisotropic Stress
• On virialization with dark energy
• Gauge-invariant analysis of perturbations in Chaplygin gas unified models of dark matter and dark energy
• Dark energy and the evolution of spherical overdensities
• Exploring the Properties of Dark Energy Using Type Ia Supernovae and Other Datasets
• Dark energy perturbations and cosmic coincidence
• Affine equation of state from quintessence and k-essence fields
• Dark Matter and Dark Energy: Summary and Future Directions
• Perturbations in cosmologies with a scalar field and a perfect fluid
• Virialization in Dark Energy Cosmology
• Voids of dark energy
• Attractors and Isocurvature Perturbations in Quintessence Models
• On the Magnitude of Dark Energy Voids and Overdensities
• Chaplygin gas with non-adiabatic pressure perturbations
• Scalar Field Dark Energy Perturbations and their Scale Dependence
• Can cosmological observations uniquely determine the nature of dark energy ?
• A new perspective on the relation between dark energy perturbations and the late-time ISW effect
• Probing Dark Energy at Galactic and Cluster Scales
• A mathematical analysis of the evolution of perturbations in a modified Chaplygin gas model
• Crisis in Cosmology : Observational Constraints on Omega and H_0
• Clustering Properties of Dynamical Dark Energy Models
• The Amplitude of Dark Energy Perturbations
• Scalar field-perfect fluid correspondence and nonlinear perturbation equations
• Voids and overdensities of coupled Dark Energy
• A Separate Universe Approach to Quintessence Perturbations

Cited by in corpus (20)

• The spherical collapse model and cluster formation beyond the $\Lambda$ cosmology: Indications for a clustered dark energy?
• Reconstructing the dark energy potential
• Evolution of Dark Energy Perturbations in Scalar-Tensor Cosmologies
• Clustering of quintessence on horizon scales and its imprint on HI intensity mapping
• Understanding the origin of CMB constraints on Dark Energy
• Growth of spherical overdensities in scalar-tensor cosmologies
• Observational constraints on quintessence models of dark energy
• Galaxy Clusters as a probe of early dark energy
• Reconstruction of late-time cosmology using Principal Component Analysis
• Evolution of perturbations in distinct classes of canonical scalar field models of dark energy
• Scalar field dark energy perturbations and the Integrated Sachs Wolfe effect
• Nonlinear spherical perturbations in Quintessence Models of Dark Energy
• Evolution of Spherical Overdensity in Thawing Dark energy Models
• Constraining Perturbative Early Dark Energy with Current Observations
• Perturbed dark energy: classical scalar field versus tachyon
• Perturbations in Tachyon Dark Energy and their Effect on Matter Clustering
• Tachyonic vs Quintessence dark energy: linear perturbations and CMB data
• Non-linear spherical collapse in tachyon models, and a comparison of collapse in tachyon and quintessence models of dark energy
• Inference of cosmological models with principal component analysis
• Perturbations In Some Dark Energy Models