Gravitational Waves from the Cosmological Quark-Hadron Phase Transition Revisited

Understand

The recent claim by the NANOGrav collaboration of a possible detection of an isotropic gravitational wave background stimulated a series of investigations searching for the origin of such a signal.

• The QCD phase transition appears as a natural candidate and in this paper the gravitational spectrum generated during the conversion of quarks into hadrons is calculated.
• Here, contrary to recent studies, equations of state for the quark-gluon plasma issued from the lattice approach were adopted.
• The duration of the transition, an important parameter affecting the amplitude of the gravitational wave spectrum, was estimated self-consistently with the dynamics of the universe controlled by the Einstein equations.