DARK FLUID: A UNIFIED FRAMEWORK FOR MODIFIED NEWTONIAN DYNAMICS, DARK MATTER, AND DARK ENERGY

Journal Article · Sat Mar 20 00:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/712/1/130· OSTI ID:21394277

Hongsheng, Zhao ^[1]

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1. Scottish University Physics Alliance, University of St. Andrews, KY16 9SS (United Kingdom)

Empirical theories of dark matter (DM) like modified Newtonian dynamics (MOND) gravity and of dark energy (DE) like f(R) gravity were motivated by astronomical data. But could these theories be branches rooted from a more general and hence generic framework? Here we propose a very generic Lagrangian of such a framework based on simple dimensional analysis and covariant symmetry requirements, and explore various outcomes in a top-down fashion. The desired effects of quintessence plus cold DM particle fields or MOND-like scalar field(s) are shown to be largely achievable by one vector field only. Our framework preserves the covariant formulation of general relativity, but allows the expanding physical metric to be bent by a single new species of dark fluid flowing in spacetime. Its non-uniform stress tensor and current vector are simple functions of a vector field with variable norm, not coupled with the baryonic fluid and the four-vector potential of the photon fluid. The dark fluid framework generically branches into a continuous spectrum of theories with DE and DM effects, including the f(R) gravity, tensor-vector-scalar-like theories, Einstein-Aether, and nuLAMBDA theories as limiting cases. When the vector field degenerates into a pure scalar field, we obtain the physics for quintessence. Choices of parameters can be made to pass Big Bang nucleosynthesis, parameterized post-Newtonian, and causality constraints. In this broad setting we emphasize the non-constant dynamical field behind the cosmological constant effect, and highlight plausible corrections beyond the classical MOND predictions.

• OSTI ID: 21394277
• Journal Information: Astrophysical Journal, Vol. 712, Issue 1; Other Information: DOI: 10.1088/0004-637X/712/1/130; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BARYONS
CAUSALITY
COSMIC PHOTONS
COSMOLOGICAL CONSTANT
COSMOLOGY
GALAXIES
GENERAL RELATIVITY THEORY
GRAVITATION
LAGRANGIAN FUNCTION
METRICS
NONLUMINOUS MATTER
NUCLEOSYNTHESIS
SCALAR FIELDS
SPACE-TIME
SPECTRA
VECTOR FIELDS
VECTORS
BOSONS
COSMIC RADIATION
ELEMENTARY PARTICLES
FERMIONS
FIELD THEORIES
FUNCTIONS
HADRONS
IONIZING RADIATIONS
MASSLESS PARTICLES
MATTER
PHOTONS
RADIATIONS
RELATIVITY THEORY
SYNTHESIS
TENSORS