We examine the possibility that a significant component of the energy density of the Universe has an equation of state different from that of matter, radiation, or cosmological constant ( Λ). An example is a cosmic scalar field evolving in a potential, but our treatment is more general. Including this component alters cosmic evolution in a way that fits current observations well. Unlike Λ, it evolves dynamically and develops fluctuations, leaving a distinctive imprint on the microwave background anisotropy and mass power spectrum.
Physical Review Letters
- Pub Date:
- February 1998
- General Relativity and Quantum Cosmology;
- High Energy Physics - Phenomenology
- revised version, with added references, to appear in Phys. Rev. Lett. (4 pages Latex, 2 postscript figures)