Gravitational waves from cosmological phase transitions

Abstract

I discuss the generation of a stochastic background of gravitational waves during a first order phase transition. I present simple general arguments which explain the main features of the gravitational wave spectrum like the $k^3$ power law growth on large scales and a estimate for the peak amplitude. In the second part I concentrate on the electroweak phase transition and argue that the nucleosynthesis bound on its gravitational wave background seriously limits seed magnetic fields which may have been generated during this transition.

14 pages, 8 Figures Proceedeings of the 1st Mediterranean Conference on Classical and Quantum Gravity (MCCQG)