Density pertubation of unparticle dark matter in the flat Universe

Abstract

The unparticle has been suggested as a candidate of dark matter. We investigated the growth rate of the density perturbation for the unparticle dark matter in the flat Universe. First, we consider the model in which unparticle is the sole dark matter and find that the growth factor can be approximated well by $f=(1+3{\omega }_u){\Omega }_u^{\gamma }$, where ${\omega }_u$ is the equation of state of unparticle. Our results show that the presence of ${\omega }_u$ modifies the behavior of the growth factor $f$. For the second model where unparticle co-exists with cold dark matter, the growth factor has a new approximation $f=(1+3{\omega }_u){\Omega }_u^{\gamma }+\alpha {\Omega }_m$ and $\alpha$ is a function of ${\omega }_u$. Thus the growth factor of unparticle is quite different from that of usual dark matter. These information can help us know more about unparticle and the early evolution of the Universe.

arXiv comment6pages, 4 figures, accepted for publication in Eur. Phys. J. C

References in corpus (40)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• The Cosmological Constant and Dark Energy
• Cosmological Constant - the Weight of the Vacuum
• The Case for a Positive Cosmological Lambda-term
• A Flat Universe from High-Resolution Maps of the Cosmic Microwave Background Radiation
• New Constraints on ${\Omega }_M$, ${\Omega }_{\Lambda }$, and w from an Independent Set of Eleven High-Redshift Supernovae Observed with HST
• Cluster Abundance Constraints on Quintessence Models
• Unparticle Physics
• Another Odd Thing About Unparticle Physics
• Large Scale Structure as a Probe of Gravitational Slip
• Distinguishing Modified Gravity from Dark Energy
• Probing Cosmic Acceleration Beyond the Equation of State: Distinguishing between Dark Energy and Modified Gravity Models
• Dark Energy versus Modified Gravity
• Testing LCDM with the Growth Function δ(a): Current Constraints
• Separating Dark Physics from Physical Darkness: Minimalist Modified Gravity vs. Dark Energy
• On the growth of linear perturbations
• Two Windows on Acceleration and Gravitation: Dark Energy or New Gravity?
• Differentiating dark energy and modified gravity with galaxy redshift surveys
• Constraining Unparticle Physics with Cosmology and Astrophysics
• Observational constraints on the linear fluctuation growth rate
• Next Generation Redshift Surveys and the Origin of Cosmic Acceleration
• Growth factor parametrization and modified gravity
• Effects of dark sectors' mutual interaction on the growth of structures
• The growth of matter perturbations in some scalar-tensor DE models
• Growth Index of DGP Model and Current Growth Rate Data
• Nonlinear growth in modified gravity theories of dark energy
• Parameterizing the Effect of Dark Energy Perturbations on the Growth of Structures
• Neutrino Mass, Dark Energy, and the Linear Growth Factor
• Growth factor parametrization in curved space
• Unparticle physics at the photon collider
• Unparticle Self-Interactions and Their Collider Implications
• Unparticle physics in diphoton production at the CERN LHC
• Imprints of deviations from the gravitational inverse-square law on the power spectrum of mass fluctuations
• Differentiating unparticles from extra dimensions via mini black hole thermodynamics
• Constraints on Unparticle Interaction from $b\to s\gamma$
• Thermal Unparticles: A New Form of Energy Density in the Universe
• Cosmological constraints on unparticle dark matter
• Unparticle Effects on Unitarity Constraints from Higgs Boson Scattering
• Stochastic contribution to the growth factor in the LCDM model

Cited by in corpus (1)

• Collider Effects of Unparticle Interactions in Multiphoton Signals