Abstract
We have investigated effects of the QCD phase transition on the relic GW spectrum applying several equations of state for the strongly interacting matter: Besides the bag model, which describes a first-order transition, we use recent data from lattice calculations featuring a crossover. Finally, we include a short period of inflation during the transition which allows for a first-order phase transition at finite baryon density. Our results show that the QCD transition imprints a step into the spectrum of GWs. Within the first two scenarios, entropy conservation leads to a step-size determined by the relativistic degrees of freedom before and after the transition. The inflation of the third scenario much stronger attenuates the high frequency modes: An inflationary model being consistent with observation entails suppression of the spectral energy density by a factor of .
6 More- Received 27 October 2010
DOI:https://doi.org/10.1103/PhysRevD.83.064030
© 2011 American Physical Society