R^(2)-corrected dark energy(DE)models in F(R)gravity have been widely investigated in recent years,which not only removes the weak singularity potentially present in DE models but also provide us with a unified pictur...R^(2)-corrected dark energy(DE)models in F(R)gravity have been widely investigated in recent years,which not only removes the weak singularity potentially present in DE models but also provide us with a unified picture of the cosmic history,including the inflationary and DE epochs.Towards the unified interpretation of dynamical DE all over the cosmic history in the class of R^(2)-corrected DE models,we explore the universal features of the scalaron dynamics in the radiation-dominated epoch,along with the chameleon mechanism,by keeping our eyes on the inflationary and DE epochs.We show that the scalaron evolution does not follow a surfing solution and is mostly adiabatic before big bang nucleosynthesis(BBN),even properly including the kick by the nonperturbative QCD phase transition,hence a catastrophic consequence claimed in the literature is not applied to this class of DE models.This is due to the presence of the gigantic scale hierarchy between R^(2) correction and DE,so is the universal feature for the class of R^(2)-corrected DE models.The prospects for the post-or onset-inflationary epoch would be pretty different from what the standard R^(2) inflationary scenario undergoes due to the presence of the chameleon mechanism.展开更多
It is widely believed that the screening mechanism is an essential feature for the modified gravity theory. Although this mechanism has been examined thoroughly in the past decade, their analyses are based on a conven...It is widely believed that the screening mechanism is an essential feature for the modified gravity theory. Although this mechanism has been examined thoroughly in the past decade, their analyses are based on a conventional fluid prescription for the matter-sector configuration. In this paper, we demonstrate a new formulation of the chameleon mechanism in F(R) gravity theory, to shed light on quantum-field theoretical effects on the chameleon mechanism as well as the related scalaron physics, induced by the matter sector. We show a possibility that the chameleon mechanism is absent in the early Universe based on a scale-invariant-extended scenario beyond the standard model of particle physics, in which a realistic electroweak phase transition, yielding the right amount of baryon asymmetry of Universe today, simultaneously breaks the scale invariance in the early Universe. We also briefly discuss the oscillation of the scalaron field and indirect generation of non-tensorial gravitational waves induced by the electroweak phase transition.展开更多
基金supported by the National Key R&D Program of China(2021YFA0718500)supported by the National Science Foundation of China(NSFC)(11975108,12047569,12147217)the Seeds Funding of Jilin University。
文摘R^(2)-corrected dark energy(DE)models in F(R)gravity have been widely investigated in recent years,which not only removes the weak singularity potentially present in DE models but also provide us with a unified picture of the cosmic history,including the inflationary and DE epochs.Towards the unified interpretation of dynamical DE all over the cosmic history in the class of R^(2)-corrected DE models,we explore the universal features of the scalaron dynamics in the radiation-dominated epoch,along with the chameleon mechanism,by keeping our eyes on the inflationary and DE epochs.We show that the scalaron evolution does not follow a surfing solution and is mostly adiabatic before big bang nucleosynthesis(BBN),even properly including the kick by the nonperturbative QCD phase transition,hence a catastrophic consequence claimed in the literature is not applied to this class of DE models.This is due to the presence of the gigantic scale hierarchy between R^(2) correction and DE,so is the universal feature for the class of R^(2)-corrected DE models.The prospects for the post-or onset-inflationary epoch would be pretty different from what the standard R^(2) inflationary scenario undergoes due to the presence of the chameleon mechanism.
基金supported by International Postdoctoral Exchange Fellowship Program at Central China Normal UniversityProject funded by China Postdoctoral Science Foundation(2018M632895)+2 种基金supported in part by the JSPS Grant-in-Aid for Young Scientists(B)(15K17645)National Science Foundation of China(NSFC)(11747308)the Seeds Funding of Jilin University.E.S.is supported by IBS under the project code,IBS-R018-D1
文摘It is widely believed that the screening mechanism is an essential feature for the modified gravity theory. Although this mechanism has been examined thoroughly in the past decade, their analyses are based on a conventional fluid prescription for the matter-sector configuration. In this paper, we demonstrate a new formulation of the chameleon mechanism in F(R) gravity theory, to shed light on quantum-field theoretical effects on the chameleon mechanism as well as the related scalaron physics, induced by the matter sector. We show a possibility that the chameleon mechanism is absent in the early Universe based on a scale-invariant-extended scenario beyond the standard model of particle physics, in which a realistic electroweak phase transition, yielding the right amount of baryon asymmetry of Universe today, simultaneously breaks the scale invariance in the early Universe. We also briefly discuss the oscillation of the scalaron field and indirect generation of non-tensorial gravitational waves induced by the electroweak phase transition.
