Dark holograms and gravitational waves

摘要: Spectra of stochastic gravitational waves (GW) generated in cosmological first-order phase transitions are computed within strongly correlated theories with a dual holographic description. The mostly used as models dark sectors. In particular, we consider the so-called Witten-Sakai-Sugimoto model, SU(N) gauge theory coupled to different matter fields both fundamental and adjoint representations. model has well-known top-down description which allows us perform reliable calculations regime. We GW spectra from bubble collisions sound arising two kinds transitions: confinement/deconfinement one chiral symmetry breaking/restoration one. Depending on parameters, find that may fall sensibility region ground-based space-based interferometers, well Pulsar Timing Arrays. latter case, signal could be compatible recent potential observation by NANOGrav. When happen at critical temperatures, characteristic double frequency peaks show up. Moreover, this case explicitly how correct redshift factors appearing formulae for power account fact adiabatic expansion first transition present times cannot assumed anymore.