Abstract
We investigate the gravitation waves produced from QCD and electroweak phase transitions in the early universe by using a 5-dimension holographic QCD model and a holographic technicolor model. The dynamical holographic QCD model is to describe the pure gluon system, where a first order confinement-deconfinement phase transition can happen at the critical temperature around 250 MeV. The minimal holographic technicolor model is introduced to model the strong dynamics of electroweak, it can give a first order electroweak phase transition at the critical temperature around 100-360 GeV. We find that for both GW signals produced from QCD and EW phase transitions, in the peak frequency region, the dominant contribution comes from the sound waves, while away from the peak frequency region the contribution from the bubble collision is dominant. The peak frequency of gravitation wave determined by the QCD phase transition is located around 10−7 Hz which is within the detectability of FAST and SKA, and the peak frequency of gravitational wave predicted by EW phase transition is located at 0.002 – 0.007 Hz, which might be detectable by BBO, DECIGO, LISA and ELISA.
Highlights
JHEP05(2018)178 local minima of a free energy coexist in a certain temperature range, the scalar field can enter into the broken phase from the symmetric phase via quantum tunnelling or thermally fluctuation, which can lead the nucleation of bubbles in the metastable sea
The peak frequency of gravitation wave determined by the QCD phase transition is located around 10−7 Hz which is within the detectability of FAST and SKA, and the peak frequency of gravitational wave predicted by EW phase transition is located at 0.002 − 0.007 Hz, which might be detectable by BBO, DECIGO, LISA and ELISA
It can be read that the energy density of GWs produced from first order QCD phase transition can reach 10−8 around the peak frequency region 3 × 10−7 Hz, which might be detected by FAST [124] and SKA, and the energy density of GWs produced from first order EW phase transition can reach 10−8 around the peak frequency 0.002 ∼ 0.007 Hz, which can be detected by BBO, DECIGO, LISA and eLISA
Summary
In order to tackle the challenging from strong coupling in the infrared (IR) of QCD, in recent decades, the anti-de Sitter/conformal field theory correspondence or the gauge/gravity duality [55,56,57] has been widely applied in investigating hadron physics, strongly coupled quark gluon plasma, QCD phase transitions and transport properties. It can be regarded as an general principle that for any d-dimensional quantum field theory (QFT) there exists a dual theory of quantum gravity living in (d + 1)-dimensions, and the gravitational description becomes classical when the QFT is strongly-coupled. This quenched DhQCD model can describe well the scalar glueball spectra [100], and all two-gluon and three-gluon glueballs including vectors and tensors [104]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
