Polarized Cosmological Gravitational Waves from Primordial Helical Turbulence

Abstract

We show that helical turbulence produced during a first-order phase transition generates circularly polarized cosmological gravitational waves (GWs). The characteristic frequency of these GWs for an extreme case of the phase transition model is around $10^{-3}$ --- $10^{-2}$ Hz with an energy density parameter as high as $10^{-12}$ --- $10^{-11}$. The possibility of detection is briefly discussed.

4 pages, 1 figure, references added, Phys. Rev. Lett. in press