Probing the Equation of State of the Early Universe with a Space Laser Interferometer

Abstract

We propose a method to probe the equation of state of the early universe and its evolution, using the stochastic gravitational wave background from inflation. A small deviation from purely radiation dominated universe (w=1⁄3) would be clearly imprinted on the gravitational wave spectrum Ω_GW(f) due to the nearly scale invariant nature of inflationary generated waves.