Gravitational radiation from cosmological phase transitions

Cavitation during a first-order phase transition, which may have occurred in the early Universe as a consequence of QCD or electroweak interactions, would have produced gravitational radiation in two ways: by generating acoustic noise in relativistic plasma, and by perturbing the expansion law on large scales. The author estimates the spectrum of the resulting stochastic background, its dependence on the parameters governing the phase transition, and the possibility of observing it above instrumental noise and other gravitational wave backgrounds of local and cosmological origin.