Production of gravitational waves during preheating with nonminimal coupling

Abstract

We study the preheating and the in-process production of gravitational waves (GWs) after inflation in which the inflaton is nonminimally coupled to the curvature in a self-interacting quartic potential with the method of lattice simulation. We find that the nonminimal coupling enhances the amplitude of the density spectrum of inflaton quanta, and as a result, the peak value of the GW spectrum generated during preheating is enhanced as well and might reach the limit of detection in future GW experiments. The peaks of the GW spectrum not only exhibit distinctive characteristics as compared to those of minimally coupled inflaton potentials but also imprint information on the nonminimal coupling and the parametric resonance, and thus the detection of these peaks in the future will provide us a new avenue to reveal the physics of the early universe.

Challenges and opportunities of gravitational-wave searches at MHz to GHz frequencies

“…Preheating can be remarkably efficient in the second case, and the GW amplitude can scale up to X GW $ O 10 À6 À 10 À7 À Á for certain coupling strengths, see Adshead et al (2020aAdshead et al ( , 2020b for more details. Production of GWs during preheating with non-minimal couplings to the scalar curvature has also been explored in Fu et al (2018). Finally, the stochastic background of GWs from preheating may develop anisotropies if the inflaton is coupled to a secondary light scalar field, see Bethke et al (2013Bethke et al ( , 2014.…”

The art of simulating the early universe. Part I. Integration techniques and canonical cases

“…• The creation of tensor perturbation representing gravitational waves [99,100,114,[139][140][141][142][143][144][145][146][147][148][149][150][151][152][153][154][155][156], as well as the dynamics of scalar metric perturbations [120][121][122][123][124][125][126][127][128][129] (possibly leading JCAP04(2021)035…”

Production of gravitational waves during preheating in the Starobinsky inflationary model

“…Different from vacuum fluctuations of tensor perturbations during inflation, the amplitude of the GW spectrum generated during preheating is independent of the energy scale of inflation which only determines the present peak frequency [25,26]. For low energy scale inflationary models, the peak frequency of GWs produced after inflation may well occur in the range which in principle can be detected by future direct detection experiments (like LIGO/VIRGO) [23,[27][28][29]. This opens a unique observational window for us to test inflation and the subsequent dynamics of the very early universe.…”