Silk damping is well known in the study of cosmic microwave background(CMB)and accounts for suppression of the angular power spectrum of CMB on large angular multipoles.In this article,we study the effect of Silk damp...Silk damping is well known in the study of cosmic microwave background(CMB)and accounts for suppression of the angular power spectrum of CMB on large angular multipoles.In this article,we study the effect of Silk damping on the scalar-induced gravitational waves(SIGWs).Resulting from the dissipation of cosmic fluid,the Silk damping notably suppresses the energy-density spectrum of SIGWs on scales comparable to a diffusion scale at the decoupling time of weakly-interacting particles.The effect offers a novel observable for probing the underlying particle interaction,especially for those mediated by heavy gauge bosons beyond the standard model of particles.We anticipate that pulsar timing arrays are sensitive to gauge bosons with mass∼10^(3)-10^(4)GeV,while space-and ground-based interferometers to those with mass∼10^(7)-10^(12)GeV,leading to essential comple-ments to on-going and future experiments of high-energy physics.展开更多
The recent stochastic signal observed jointly by NANOGrav,parkes pulsar timing array,European pulsar timing array,and Chinese pulsar timing array can be accounted for by scalarinduced gravitational waves(SIGWs).The so...The recent stochastic signal observed jointly by NANOGrav,parkes pulsar timing array,European pulsar timing array,and Chinese pulsar timing array can be accounted for by scalarinduced gravitational waves(SIGWs).The source of the SIGWs is from the primordial curvature perturbations,and the main contribution to the SIGWs is from the peak of the primordial curvature power spectrum.To effectively model this peak,we apply the Taylor expansion to parameterize it.With the Taylor expansion parameterization,we apply Bayesian methods to constrain the primordial curvature power spectrum based on the NANOGrav 15 year data set.The constraint on the primordial curvature power spectrum possesses a degree of generality,as the Taylor expansion can effectively approximate a wide range of function profiles.展开更多
It is well known that a primordial black hole(PBH)can be generated in the inflation process of the early universe,especially when the inflation field has a number of non-trivial features that could break the slow-roll...It is well known that a primordial black hole(PBH)can be generated in the inflation process of the early universe,especially when the inflation field has a number of non-trivial features that could break the slow-roll condition.In this study,we investigate a toy model of inflation with bumpy potential,which has one or several bumps.We determined that the potential with multi-bump can generate power spectra with multi-peaks in small-scale region,which can in turn predict the generation of primordial black holes in various mass ranges.We also consider the two possibilities of PBH formation by spherical and elliptical collapses.Finally,we discuss the scalar-induced gravitational waves(SIGWs)generated by linear scalar perturbations at second-order.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12175243)the National Key R&D Program of China(Grant No.2023YFC2206403)+1 种基金the Science Research Grants from the China Manned Space Project(Grant No.CMS-CSST-2021-B01)the Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB15)。
文摘Silk damping is well known in the study of cosmic microwave background(CMB)and accounts for suppression of the angular power spectrum of CMB on large angular multipoles.In this article,we study the effect of Silk damping on the scalar-induced gravitational waves(SIGWs).Resulting from the dissipation of cosmic fluid,the Silk damping notably suppresses the energy-density spectrum of SIGWs on scales comparable to a diffusion scale at the decoupling time of weakly-interacting particles.The effect offers a novel observable for probing the underlying particle interaction,especially for those mediated by heavy gauge bosons beyond the standard model of particles.We anticipate that pulsar timing arrays are sensitive to gauge bosons with mass∼10^(3)-10^(4)GeV,while space-and ground-based interferometers to those with mass∼10^(7)-10^(12)GeV,leading to essential comple-ments to on-going and future experiments of high-energy physics.
基金supported in part by the National Natural Science Foundation of China under Grant No.12305060the Talent-Introduction Program of Hubei Polytechnic University under Grant No.19xjk25R。
文摘The recent stochastic signal observed jointly by NANOGrav,parkes pulsar timing array,European pulsar timing array,and Chinese pulsar timing array can be accounted for by scalarinduced gravitational waves(SIGWs).The source of the SIGWs is from the primordial curvature perturbations,and the main contribution to the SIGWs is from the peak of the primordial curvature power spectrum.To effectively model this peak,we apply the Taylor expansion to parameterize it.With the Taylor expansion parameterization,we apply Bayesian methods to constrain the primordial curvature power spectrum based on the NANOGrav 15 year data set.The constraint on the primordial curvature power spectrum possesses a degree of generality,as the Taylor expansion can effectively approximate a wide range of function profiles.
基金Supported by the National Natural Science Foundation of China(11653002,11875141),partially the Fundamental Research Funds for the Central Universities(Innovation Funded Projects)(2020CXZZ105)。
文摘It is well known that a primordial black hole(PBH)can be generated in the inflation process of the early universe,especially when the inflation field has a number of non-trivial features that could break the slow-roll condition.In this study,we investigate a toy model of inflation with bumpy potential,which has one or several bumps.We determined that the potential with multi-bump can generate power spectra with multi-peaks in small-scale region,which can in turn predict the generation of primordial black holes in various mass ranges.We also consider the two possibilities of PBH formation by spherical and elliptical collapses.Finally,we discuss the scalar-induced gravitational waves(SIGWs)generated by linear scalar perturbations at second-order.
