Can cosmic acceleration be caused by exotic massless particles?

Abstract

To describe dark energy we introduce a fluid model with no free parameter on the microscopic level. The constituents of this fluid are massless particles which are a dynamical realisation of the unextended $D=(3+1)$ Galilei algebra. These particles are exotic as they live in an enlarged phase space. Their only interaction is with gravity. A minimal coupling to the gravitational field, satisfying Einstein's equivalence principle, leads to a dynamically active gravitational mass density of either sign. A two-component model containing matter (baryonic and dark) and dark energy leads, through the cosmological principle, to Friedmann-like equations. Their solutions show a deceleration phase for the early universe and an acceleration phase for the late universe. We predict the Hubble parameter $H(z)/H_0$ and the deceleration parameter $q(z)$ and compare them with available experimental data. We also discuss a reduced model (one component dark sector) and the inclusion of radiation. Our model shows no stationary modification of Newton's gravitational potential.

References in corpus (21)

• Dynamics of dark energy
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Quantum Gravity at a Lifshitz Point
• Dark Energy and the Accelerating Universe
• Improved Cosmological Constraints from New, Old and Combined Supernova Datasets
• Dark torsion as the cosmic speed-up
• Improved Dark Energy Constraints from ~100 New CfA Supernova Type Ia Light Curves
• Extended Theories of Gravity and their Cosmological and Astrophysical Applications
• Reconstructing Dark Energy
• Avoiding Dark Energy with 1/R Modifications of Gravity
• Approaches to Understanding Cosmic Acceleration
• The Dynamics of Quintessence, The Quintessence of Dynamics
• Kinematic Constraints to the Transition Redshift from SNe Ia Union Data
• Acceleration-Extended Galilean Symmetries with Central Charges and their Dynamical Realizations
• Dark Energy or Apparent Acceleration Due to a Relativistic Cosmological Model More Complex than FLRW?
• Astrophysical Configurations with Background Cosmology: Probing Dark Energy at Astrophysical Scales
• Constraints on Kinematic Model from Recent Cosmic Observations: SN Ia, BAO and Observational Hubble Data
• Giving up the ghost
• Conformal Galilean-type algebras, massless particles and gravitation
• Dark Energy vs. Dark Matter: Towards a Unifying Scalar Field?
• Critical Thoughts on Cosmology

Cited by in corpus (3)

• Self-gravitating darkon fluid with anisotropic scaling
• Velocity and velocity bounds in static spherically symmetric metrics
• Conformal Galilean-type algebras, massless particles and gravitation