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 ${\Omega }_{GW}(f)$ due to the nearly scale invariant nature of inflationary generated waves.

Comments: 10 pages, 1 figure