요약본 (Summary):
This paper explores inflationary observables in F(R) gravity by constructing a modified gravity model with linear, quadratic, cubic, and quartic terms. The presented model satisfies current observational bounds from PLANCK and BICEP3, offering lower values for the tensor-to-scalar ratio compared to existing models. The authors transform the f(R) model into an Einstein frame theory and calculate key inflationary observables such as the spectral index and tensor-to-scalar ratio, which are then compared to experimental bounds. This study contributes to the development of new inflationary models in the context of F(R) gravity.
이 논문은 선형, 2 차, 입방 및 쿼 트릭 용어로 변형 된 중력 모델을 구성함으로써 F (R) 중력의 인플레이션 관찰 가능성을 탐구합니다. 제시된 모델은 Planck 및 BICEP3의 현재 관측 경계를 충족 시키며 기존 모델에 비해 텐서 대 스칼라 비율에 대한 낮은 값을 제공합니다. 저자는 F (R) 모델을 아인슈타인 프레임 이론으로 변환하고 스펙트럼 지수 및 텐서 대 스칼라 비율과 같은 주요 인플레이션 관찰 가능성을 계산 한 다음 실험 경계와 비교됩니다. 이 연구는 F (r) 중력의 맥락에서 새로운 인플레이션 모델의 개발에 기여합니다.
Excerpt from PDF:
Inflationary observables in F(R) gravity E. D´ıaz, O. Meza-Aldama Sibatel Communications 303 W Lincoln Ave No.140, Anaheim, CA 92805 (Dated: December 30, 2024) We present phenomenological signatures for a modified gravity model f(R), constructed with linear, quadratic, cubic and quartic terms. The obtained signatures satisfy current phenomenological bounds reported by PLANCK and BICEP3. Furthermore, two of the model solutions σ1 and σ2 seem to favor a much lower value for the tensor-to-scalar ratio 0.0005 < rσ1 < 0.0015 and rσ2 < 0.00015 than the current reported experimental bounds. The results we obtained are quantitatively similar to those presented in previous studies for R3 models. PACS numbers: 98.80.Cq I. INTRODUCTION Inflationary cosmology [1, 3] offers an explanation for the observed flatness, homogeneity, and isotropy of the universe. The way in which one may construct an inflationary model can be accomplished in a myriad of ways, one could add higher-order terms to the inflationary potential V (ϕ) [4], some of which might be coupled to the Higgs model, others might have an origin from SUGRA [5]. In this work, we explore an F(R) theory [2] in which we added higher-order Ricci scalar terms as opposed to just having the linear R term given in Einstein gravity. Several f(R) models, such as the Starobinsky model f(R) = R + αR2, have been extensively studied and are known to produce predictions consistent with the latest observational data from the Planck satellite, particularly the spectral index and tensor-to-scalar ratio r [3], [7]. These models can also be recast in the Einstein frame, where they are equivalent to scalar-tensor theories, further elucidating their connection to traditional scalar field inflationary scenarios [8]. In recent years, higher order polynomial functions have been put forward and their implications uncovered [12], [13]. The observational measurements of the spectral index of curvature perturbations reported by PLANCK ns = 0.9649 ± 0.0042, as well as the upper bound on the tensor-to-scalar ratio r < 0.072 [7], have been instrumental in the process of building new inflationary models. Continuing with this process, the BICEP/Keck2021 upper bound on r < 0.036 at 95% C.L. [9], offers a great opportunity to see what implications this has on new models. This is why we set about and looked at a modified gravity f(R) model. This formalism offers one of the simplest ways upon which new inflationary models can be constructed. In this work we study some of the implications of a quartic polynomial function f(R), namely f(R) = R + 1 2αR2 + 1 3βR3+ 1 4γR4. The paper is structured as follows: In the next section we present a brief summary of generic inflationary f(R) models, how to transform them into a regular Einstein frame theory and how to perform the calculation of the main inflationary observables in that frame. In section 3, we give the specific expressions for our quartic model. In section 4 we obtain the slow roll parameters and from them we calculate the spectral index and the tensor-to-scalar ratio, which are ...더보기
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번역 (Translation):
인플레이션 관측 가능 F (r) 중력 E. D´ıaz, O. Meza-Aldama Sibatel Communications 303 W Lincoln Ave No.140, Anaheim, CA 92805 (날짜 : 2024 년 12 월 30 일) 우리는 수정 된 중력 모델 F (r)에 대한 현상 학적 서명을 제시하며, 이는 선형, 입방 및 사각형으로 구성됩니다. 획득 된 시그니처는 Planck 및 BICEP3에 의해보고 된 전류 현상 학적 범위를 충족시킨다. 또한, 모델 솔루션 σ1 및 σ2 중 2 개는 현재보고 된 실험 범위보다 텐서 대 스칼라 비율 0.0005 이 논문은 arXiv에서 제공되는 자료를 바탕으로 업로드되었습니다.
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