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