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Jureeporn Yuennan

Publications and source records attributed to Jureeporn Yuennan.

11 recordsLinked to original sources

arXiv2026

Constraining $\beta$-Exponential Inflation with the latest ACT observations

Recent observations from the Atacama Cosmology Telescope (ACT), especially when combined with DESI baryon acoustic oscillation data, indicate a scalar spectral index $n_s$ higher than the value reported by \textit{Planck} 2018, placing tension on universal inflationary attractor models. Motivated by this discrepancy, we investigate the inflationary predictions of the $\beta$-exponential potential, $V(\phi)=V_0\left(1-\lambda\beta\phi/M_p\right)^{1/\beta}$ considering both minimally and non-minimally coupled realizations. This potential generalizes standard exponential inflation and naturally arises in braneworld scenarios. We derive analytical expressions for the slow-roll parameters and inflationary observables using a perturbative expansion in the non-minimal coupling $\xi$, and validate these results through numerical calculations. In the minimally coupled case, the model predicts $n_s \simeq 0.976$ and $r \simeq 0.035$ for $N=50$ and moderate values of \beta, remaining compatible with ACT+DESI constraints at the 1\sigma level while yielding a spectral tilt larger than the universal attractor prediction. Introducing a small non-minimal coupling significantly improves agreement with observations by suppressing the tensor-to-scalar ratio while preserving the enhanced scalar tilt. For $N=60, \lambda \sim 0.3-0.5$, and $\beta \sim O(1-5)$, the non-minimally coupled model yields $n_s \simeq 0.974-0.976$ and $r \lesssim 0.03$, comfortably consistent with ACT, DESI, and BICEP/Keck bounds. Our results show that the $\beta$-exponential potential, especially when implemented with a non-minimal coupling, exhibits good agreement with the latest CMB observations. Our inflationary predictions of the non-minimal model of $n_s$ and $r$ confirming the leading-order contributions in $\xi$ are sufficient to capture the essential features of both $r$ and $n_s$ in observationally relevant regimes.

gr-qc↗

arXiv2025

Constraining non-minimally coupled squared-Quartic Hilltop Inflation in light of ACT observations

The combination of the data from the Dark Energy Spectroscopic Instrument (DESI) with the recent measurements from the Atacama Cosmology Telescope (ACT) indicate that the scalar spectral index \( n_s \) has a larger value than the Planck 2018 which leads to tension within standard inflationary models. In this study in order to explain the new data, We consider the squared-Quartic Hilltop inflation potential \( V(\phi) = V_0 [1 - \lambda (\phi/M_p)^4]^2 \) within the Einstein and Jordan frames. In the Jordan frame we introduce the coupling term \( \xi \phi^2 R \) and we calculate analytic expressions for the slow-roll parameters, scalar spectral index, and tensor-to-scalar ratio on the weak and strong coupling regimes. In the weak limit (\( \xi \ll 1 \)), perturbative corrections slightly increase \( n_s \) and suppress \( r \), leading to \( n_s \simeq 0.9743 \) and \( r \sim 7.8 \times 10^{-5} \) for representative parameters \( \lambda = 10^{-3}, \xi = 10^{-3}, {\cal N} = 117 \), values which are in agreement with the joint Planck--ACT--DESI (P-ACT-LB) constraints. On the other hand, for a strong coupled (\( \xi \gg 1 \)), the conformal rescaling provides an exponentially flat potential plateau, which allows us to calculate \( n_s \approx 0.9743 \) with \( r \lesssim 5 \times 10^{-4} \) for \( {\cal N} = 65{-}70 \), consistent with ACT and BK18 bounds. The associated energy scale of inflation, \( V_0^{1/4} \sim 10^{-3}{-}10^{-2} M_p \), remains compatible with high-scale inflationary scenarios.

astro-ph.CO↗

arXiv2025

Radiative-Corrected Higgs Inflation in Light of the Latest ACT Observations

Recent measurements from the Atacama Cosmology Telescope (ACT), particularly when combined with DESI baryon acoustic oscillation data, have reported a scalar spectral index $n_s$ slightly higher than that inferred by {\it Planck}~2018, suggesting a mild tension with the predictions of standard inflationary attractor models. In this work, we revisit the quantum-corrected Higgs inflation scenario within the framework of a non-minimally coupled scalar field theory. Starting from the one-loop effective action, we incorporate radiative corrections through the anomalous scaling parameter ${\bf A_I}$ and derive analytic expressions for the inflationary observables $n_s$ and $r$ in the Einstein frame. Our analysis demonstrates that quantum corrections naturally shift $n_s$ toward higher values while keeping the tensor-to-scalar ratio $r$ suppressed. For ${\cal N} = 60$, the model predicts $n_s \simeq 0.9743$ and $r \simeq 5.4\times10^{-3}$, in excellent agreement with the latest ACT+DESI (P-ACT-LB) data and fully consistent with the \textit{Planck}~2018 limit $r < 0.036$. The derived constraint $4.36\times10^{-10} < \lambda/\xi^{2} < 10.77\times10^{-10}$ confirms the robustness of the quantum-corrected Higgs framework and indicates that near-future CMB polarization experiments such as CORE, AliCPT, LiteBIRD, and CMB-S4 will be able to probe the predicted parameter space with high precision.

astro-ph.CO↗

arXiv2025

ACT Constraints on Marginally Deformed Starobinsky Inflation

We investigate the inflationary phenomenology of a marginally deformed Starobinsky model, motivated by quantum corrections to the $R^{2}$ term, in light of the latest cosmological observations. In this framework, the inflationary potential acquires a small deformation parameter, $\gamma$, which shifts predictions away from the exact Starobinsky limit. Using the slow-roll formalism, we derive analytic expressions for the spectral index $n_{s}$ and tensor-to-scalar ratio $r$ and confront them with constraints from Planck, ACT, and DESI data. Our analysis shows that nonzero values of $\gamma$ raise both $n_{s}$ and $r$, thereby alleviating the $\gtrsim 2\sigma$ tension between the Starobinsky $R^{2}$ scenario and the ACT+DESI (P-ACT-LB) measurements, which favor $n_{s} \simeq 0.9743 \pm 0.0034$. For $N \sim 60$ $e$-foldings, the model consistently reproduces the observed amplitude of primordial perturbations while predicting tensor contributions within current observational bounds. We also demonstrate that the deformation softens the otherwise severe fine-tuning of the quartic self-coupling in minimally coupled inflation. The parameter range $\gamma \sim \mathcal{O}(10^{-3})$-$\mathcal{O}(10^{-2})$ emerges as phenomenologically viable, providing a natural extension of Starobinsky inflation compatible with present data. We conclude that marginally deformed $R^{2}$ inflation remains a compelling and testable candidate for the primordial dynamics of the Universe, with future CMB and gravitational-wave observations expected to further probe its parameter space.

gr-qc↗

arXiv2025

Quantum-Corrected $\phi^{4}$ Inflation in Light of ACT Observations

Recent measurements from the Atacama Cosmology Telescope (ACT), combined with Planck and DESI data, suggest a scalar spectral index $n_s$ higher than the Planck 2018 baseline, thereby placing conventional attractor-type inflationary models such as Starobinsky $R^2$ and Higgs inflation under increasing tension at the $\gtrsim 2\sigma$ level. In this work, we examine quantum-corrected $\phi^4$ inflation with a non-minimal coupling to gravity. Introducing an anomalous scaling parameter $\gamma$ to capture quantum corrections to the effective potential, we derive analytic expressions for the inflationary observables $n_s$ and $r$. Confronting these predictions with ACT, Planck, and BAO+lensing constraints, we demonstrate that modest values of $\gamma$ can raise $n_s$ into the ACT-preferred range while maintaining a strongly suppressed tensor-to-scalar ratio. For instance, with $N=60$ and $\gamma\simeq 0.006$, the model predicts $n_s\simeq 0.974$ and $r\simeq 0.007$, in excellent agreement with current bounds. We further investigate preheating dynamics, focusing on particle production via parametric resonance in quantum-corrected $\phi^4$ inflation with a non-minimal coupling to gravity. In this scenario, the inflaton $\phi$ couples to an additional scalar $\chi$ through an interaction $g^{2}\phi^{2}\chi^{2}$. In Minkowski spacetime, the resonance dynamics reduce to the Mathieu equation, and we find that broad resonance can be readily achieved, leading to efficient particle production.

astro-ph.CO↗

arXiv2025

Traversable Wormholes in non-minimal Einstein-Yang-Mills Gravity: Geometry, Energy Conditions, and Gravitational Lensing

This work presents a new class of static, spherically symmetric traversable wormhole solutions within the framework of non-minimal Einstein-Yang-Mills (EYM) gravity, where the SU(2) Yang-Mills field is purely magnetic. By adopting a constant redshift function and introducing a direct coupling between the Ricci scalar and the Yang-Mills field strength, we investigate the role of the non-minimal coupling constant $\xi$ and the magnetic charge $Q$ in shaping the wormhole geometry. Our analysis shows that for small values of $\xi$, the flare-out and throat conditions can be satisfied, allowing physically viable traversable wormholes without requiring externally introduced exotic matter. The Arnowitt-Deser-Misner (ADM) mass is evaluated, revealing that for $\xi < 0.01$ it grows monotonically with charge, whereas for $\xi \gtrsim 0.01$ it decreases with increasing charge, signaling a reduction in the total mass-energy of the system. An examination of the energy conditions indicates localized violations of the null and weak energy conditions at the throat, while the strong energy condition remains satisfied. Finally, the study of gravitational lensing confirms that the deflection angle of light is consistently positive, reflecting the overall attractive nature of the wormhole gravitational field. These results highlight the significant role of non-minimal gauge-gravity couplings in enabling traversable wormholes with distinct observational signatures.

gr-qc↗

arXiv2024

Kiselev-inspired Wormholes

In this study, we investigate traversable wormholes inspired by the Kiselev framework, which extends classical black hole solutions by incorporating anisotropic fluids. These exotic fluids play a crucial role in cosmology, particularly in explaining phenomena such as the accelerated expansion of the universe. We generalize the Kiselev framework to static, spherically symmetric traversable wormholes and analyze their properties under two distinct models of the redshift function: a constant redshift function and one that varies inversely with the radial coordinate. We examine the energy conditions-specifically the Null Energy Condition (NEC), Weak Energy Condition (WEC), and Strong Energy Condition (SEC)-for these models, demonstrating that only certain exotic fluids can sustain the wormhole structure. Furthermore, we quantify the amount of exotic matter required to maintain these wormholes using the volume integral quantifier and compare our results with other wormhole models. Additionally, we compute the effective potential for photons in Kiselev-inspired wormholes under both redshift function models and analyze their implications for weak gravitational lensing. Our findings suggest that Kiselev-inspired wormholes could serve as viable candidates for exotic geometries, potentially paving the way for future observational verification.

gr-qc↗

arXiv2024

Warm non-minimally coupled Peccei-Quinn Inflation and de Sitter Swampland Conjecture

In this study, we explore the dynamics of warm inflation within a non-minimally coupled Peccei-Quinn (PQ) framework and evaluate its compatibility with the de Sitter Swampland Conjecture. Our model incorporates a PQ scalar field that is non-minimally coupled to gravity, facilitating inflation through a dissipative process that sustains a thermal bath, thereby distinguishing it from conventional cold inflation. We analyze the dissipation coefficient defined as $Γ(T, σ) = C_n T^n σ^p M^{1-n-p}$, where $C_n$ is a dimensionless constant, $M$ is a mass scale, and $n$ and $p$ are numerical powers. Our investigation focuses on three specific cases: (a) A temperature-dependent dissipation coefficient with an inverse relation, $Γ= C_{-1}\,σ^2/T$, where $n=-1$ and $p=2$; (b) A dissipation coefficient linear in field $ϕ$, $Γ= C_{0} σ$, where $n=0$ and $p=1$; and (c) A dissipation coefficient linear in temperature $T$, $Γ= C_{1} T$, where $n=1$ and $p=0$. By examining the slow-roll dynamics in these inflationary scenarios, we derive essential cosmological parameters, including the scalar spectral index and the tensor-to-scalar ratio. We compare our results with the latest observational data from Planck 2018. Our findings suggest that the model is consistent with observational constraints while simultaneously satisfying the de Sitter Swampland conditions.

gr-qc↗

arXiv2024

Gravity Rainbow Effects on Higher Curvature Modification of R2 inflation

In this work, we study several extensions of the higher curvature modification of $R^{2}$ inflation in the context of gravity's rainbow. We modify the $(R+R^{2})$ model by adding an $f_{1}R^3$-term, an $f_{2}R^4$-term, and an $f_{3}R^{3/2}$-term to the original model. We calculate the inflationary observables and confront them using the latest observational bounds from Planck 2018 data. We assume the rainbow function of the form $\tilde{f}=1+\left(\frac{H}{M}\right)^{λ}$ with $λ$ being a rainbow parameter and $M$ a mass-dimensional parameter. We demonstrate that the power spectrum of curvature perturbation relies on the dimensionless coefficient $f_{i},\,i=1,2,3$, a rainbow parameter $λ$ and a ratio $H/M$. Likewise, the scalar spectral index $n_s$ is affected by both $f_{i}$ and the rainbow parameter. Moreover, the tensor-to-scalar ratio $r$ is solely determined by the rainbow parameter. Interestingly, by ensuring that $n_s$ aligns with the Planck collaboration's findings at the $1σ$ confidence level, the tensor-to-scalar ratio could reach up to $r\sim 0.01$, which is possibly measurable for detection in forthcoming Stage IV CMB ground experiments and is certainly feasible for future dedicated space missions.

gr-qc↗

arXiv2022

Composite Inflation and further refining dS swampland conjecture

A natural combination of the first and second derivatives of the scalar potential was achieved in a framework of an alternative refined de Sitter conjecture recently proposed in the literature. In this work, we study various inflation models in which the inflaton is a composite field emerging from various strongly interacting field theories. We then examine if these three models of inflation can satisfy this further refining de Sitter swampland conjecture or not. Regarding our analysis with proper choices of parameters $a,\,b=1- a$ and $q$, we find that some inflationary models are in strong tension with the refined Swampland conjecture. However, all of them can always satisfy the alternative refined de Sitter conjecture. Therefore, one may expect that all inflationary models might all be in landscape since the further refining de Sitter swampland conjecture is satisfied.

gr-qc↗

arXiv2022

Further refining Swampland Conjecture on inflation in general scalar-tensor theories of gravity

An alternative refined de Sitter conjecture giving rise to a natural combination of the first and second derivatives of the scalar potential was proposed recently by David Andriot and Christoph Roupec (Fortsch. Phys. 67 (2019) no.1-2, 1800105). In this work, we study the inflation models in a general scalar-tensor theory with exponential and hyperbolic tangent forms of potential as well as model with quantum corrected potential and examine whether these three models of inflation can satisfy this further refining de Sitter swampland conjecture or not. Regarding our analysis with proper choices of parameters with proper choices of parameters $a,b=1-a$ and $q$, we find that these three inflationary models can always satisfy this new refined swampland conjecture. Therefore, all three inflationary models might all be in landscape since the further refining de Sitter swampland conjecture is satisfied.

hep-th↗