arXiv subjects

Phongpichit Channuie

Publications and source records attributed to Phongpichit Channuie.

At least 55 records · Page 3Linked to original sources

arXiv2023

Rotating traversable wormhole geometries in the presence of three-form fields

In this work, we study the rotating wormhole geometries supported by a three-form field. We demonstrate for particular choices of parameters that it is possible for the matter fields threading the wormhole to satisfy the null and weak energy conditions throughout the spacetime, when the three-form field is present. In this case, the form field is interpreted as supporting the wormhole and all the exoticity is confined to it. Thus, the three-form curvature terms, which may be interpreted as a gravitational fluid, sustain these wormhole geometries. Additionally, we also address the ergoregion of the solutions.

gr-qc↗

arXiv2023

Nonminimally-coupled warm Higgs inflation: Metric vs. Palatini Formulations

In this work, we study the non-minimally-coupled Higgs model in the context of warm inflation scenario on both metric and Palatini approaches. We particularly consider a dissipation parameter of the form $Γ=C_{T}T$ with $C_{T}$ being a coupling parameter and focus only on the strong regime of the interaction between inflaton and radiation fluid. We compute all relevant cosmological parameters and constrain the models using the observational Planck 2018 data. We discover that the $n_s$ and $r$ values are consistent with the observational bounds. Having used the observational data, we constrain a relation between $ξ$ and $λ$ for the non-minimally-coupled warm Higgs inflation in both metric and Palatini cases. To produce $n_s$ and $r$ in agreement with observation, we find that their values are two orders of magnitude higher than those of the usual (cold) non-minimally-coupled Higgs inflation.

gr-qc↗

arXiv2023

On preheating after inflation in general scalar-tensor theories of gravity

In this work, we investigate the preheating mechanism after inflation in general scalar-tensor theories of gravity. In the present scenario, we consider two-field scenario and then derive the potential of exponential and hyperbolic tangent forms. We study the evolution of the background system when the back reaction on the background field is neglected. We examine the particle production due to parametric resonances in both models. We find that in Minkowski space the stage of parametric resonances can be described by the Mathieu equation. Finally, we demonstrate that parametric resonances in our models are sufficiently broad possible for the exponential growth of the number of particles.

gr-qc↗

arXiv2023

Observational Constraints and Preheating in Cuscuton Inflation

We study cuscuton inflation for the models where the potential of the cuscuton takes quadratic and exponential forms. We find that for the quadratic potential, a scalar spectral index $n_s$ is not affected by cuscuton at the leading order in the slow-roll inflation models. However, a tensor-to-scalar ratio $r$ can be suppressed. For the exponential potential of cuscuton, we find the condition for which the inflation has a graceful exit. Under this condition, the observational predictions in this model differ by a few percent from those found in standard inflation. We also examine the particle production due to parametric resonances in both models. We find that in Minkowski space the stage of parametric resonances can be described by the Mathieu equation. For the case where the cuscuton has quadratic potential, the amplitude of the driving force in the Mathieu equation has a similar form as that in standard inflation. Nevertheless, in the case of exponential potential, the amplitude of the driving force decreases faster than that in the standard case. However, parametric resonances in our models can be sufficiently broad possible for the exponential growth of the number of particles. We briefly discuss the case in which the expansion of space is taken into account.

gr-qc↗

arXiv2023

AdS to dS phase transition mediated by thermalon in Einstein-Gauss-Bonnet gravity from Renyi statistics

In this work, we present the possible existence of a thermalon phase transition between anti-de Sitter (AdS) to de Sitter (dS) vacua in Einstein-Gauss-Bonnet gravity by considering the Rényi statistics. A thermalon changes the asymptotic structure of spacetimes via the bubble nucleation of spherical thin-shells which host a black hole in the interior. All relevant thermodynamical quantities are computed in terms of the Renyi statistics in order to demonstrate the possible existence of the AdS to dS phase transition. In addition, we also comment on the behaviors of the phase transitions in the Renyi statistics.

hep-th↗

arXiv2022

Warm deformed $R^{2}$ inflation

In this work, we study warm inflationary scenario based on a deformation of $R^{2}$ gravity. We start considering $R^{p}$ and assume $p=2(1+δ)$ with $δ\ll 1$ so that we simply obtain warm $R^{2}$ inflation when setting $δ=0$. We then derive the potential in the Einstein frame and consider a dissipation parameter of the form $Γ= C_{1}T$ with $C_1$ being a coupling parameter. We focus only on the strong regime of which the interaction between inflaton and radiation fluid has been taken into account. We compute inflationary observables and constrain the parameters of our model using latest observational data reported by Planck. From our analysis, we discover that with proper choices of parameters the derived $n_s$ and $r$ are in good agreement with the Planck 2018 observational constraints. Particularly, we constrain the potential scale $U_{0}$ of the models.

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

Gravitational lensing by traversable wormholes supported by three-form fields

In this paper, we study the deflection angle of light by traversable wormholes, which are supported by the three-form fields. The specific forms of the redshift and shape functions that produce results compatible with the energy conditions at throat of the wormholes are used. Having used the well-defined parameter sets of the three-form wormholes, we investigate the photon geodesic motion under the effective potential of the wormhole background. As a result, we discover that the radius of the photon sphere is a very useful observable that is used to analyze the geometrical structures of a physical wormhole.

gr-qc↗

arXiv2022

Adiabatic invariant approach on Friedmann cyclic universe

Oscillating or cyclic models of the universe were inspired by Friedmann's seminal paper of 1922. The model supposes a closed universe. In this work, we study Friedmann closed universe using the adiabatic invariant approach. We start revisiting the cosmological force proposed by N. Rosen and derive the Lagrangian density from Rosen's concepts of cosmological force. Importantly, we introduce the Noether gauge symmetry followed by the Rund-Traumann identity (RTI) and adiabatic invariant approach to examine the cyclic models. We consider a single component form of relativistic matter (stiff matter) at $a(t=0)$ and $a(t=T)$, and surprisingly discover the world period is given by $\sim 15.8$ Gy which is very close to that computed using the Friedmann's formula for the cyclic universe.

gr-qc↗

arXiv2022

Charged traversable wormholes supported by Casimir energy with and without GUP corrections

In this paper, we investigate new exact and analytic solutions of the Einstein Maxwell field equations describing Casimir wormholes with and without the effect of the Generalized Uncertainty Principle (GUP). We consider a specific type of the GUP relations and study three specific models of the redshift function along with two different EoS of state. Here we obtain a class of asymptotically flat Casimir wormhole solutions with and without GUP corrections under the effect of electric charge. Furthermore we check the null, weak, strong and dominant energy conditions at the wormhole throat of radius, and show at the wormhole throat that the classical energy conditions are violated by some arbitrary small quantity. We also examine the wormhole geometry with semiclassical corrections by using embedding diagrams. We use the volume integral quantifier to quantify the amount of the exotic matter near the wormhole throat. Additionally, we investigate exotic fluid near WH throat using the so called exoticity parameter and discuss the speed of sound.

gr-qc↗

arXiv2022

Refined Swampland conjecture in deformed Starobinsky gravity

In order to validate or invalidate a large class of low energy effective theories, the Swampland conjecture has attracted significant attention, recently. It can be stated as inequalities on the potential of a scalar field which is conjectured to satisfy certain constraints. In this work, we discuss the theoretical viability of deformed Starobinky gravity in light of the refined Swampland conjectures. We consider the deformation of the form $f(R)\sim R^{2(1-α)}$ with $α$ being a constant. We then constrain $α$ using the spectral index of curvature perturbation $n_s$ and the tensor-to-scalar ratio $r$. We demonstrate that the model under consideration is in strong tension with the refined swampland conjecture. However, regarding our analysis with proper choices of parameters $a,\,b=1- a$ and $q$, we discover that the model can always satisfy this new refined swampland conjecture. Therefore, the model might be in landscape since the further refining de Sitter swampland conjecture is satisfied.

hep-th↗

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↗

arXiv2022

Warm inflation in general scalar-tensor theory of gravity

In this work, we investigate warm inflationary models in the context of a general scalar-tensor theory of gravity which is coupled to radiation through a dissipation term. We first derive the potential of exponential and hyperbolic tangent forms. We consider a dissipation parameter of the form $Γ= C_{1}T$ with $C_1$ being a coupling parameter and focus only on the strong regime of which the interaction between inflaton and radiation fluid has been taken into account. We compute inflationary observables and constrain the parameters of our model using current Planck 2018 data. From our analysis, we discover that the weak coupling limit $ξ\ll 1$ is needed in order to have the derived $n_s$ and $r$ consistent with the Planck 2018 observational constraints. Particularly, we constrain the potential scale $V_{0}$ of the models.

gr-qc↗

arXiv2022

Lab at Home of fluid draining with Tracker

The pandemic caused by the SARS-CoV-2 virus has threaten the face-to-face teaching activity in both schools and universities. The transformation from face-to-face classes to online activities yielded inefficient outcomes from the activities. Particularly, a key issue was organizing laboratory activities without accessing the labs. In this paper, we propose how to overcome this problem by enabling the students to perform physics experiments of fluid draining at home. In other words, the use of equipment commonly available at home or that can be purchased at a low price is practically plausible. In the present work, we do an experimental investigation of liquid draining through a hole of a container. From an analyzing step, we introduce a freely-accessible video analysis software, Tracker, to obtain accurate results. Interestingly, we observe the effects of viscosity causing a delay of draining time of liquids. Our study shows that a ratio of open-space radius of the container to the hole radius, $\sqrtλ$, can be used to determine a draining time.

physics.ed-ph↗

arXiv2021

Thermalon mediated AdS to dS phase transitions in Einstein-Gauss-Bonnet-massive gravity

In this work, gravitational phase transition emerging from anti de-Sitter (AdS) to de-Sitter (dS) vacua in Einstein-Gauss-Bonnet-massive gravity (EGBMG) is considered. We determine the location of thermalon (a static bubble solution in Euclidean space) which exists in casually connected two regions of the spacetime. The thermalon plays a major role in gravitational phase transition by inducing the decay of the negative effective cosmological constant to the positive one due to the higher-order gravity effects. The thermodynamics phase space of the Hawking temperature and free energy is investigated in details. We find that the free energy of the thermalon is always negative at the maximum of Hawking temperature for all possible values of the Gauss-Bonnet couplings. This means that the phase transition mediated by thermalon from AdS to dS asymptotics is inevitable according to the presence of the massive gravity. More importantly, the parameters of the massive gravity behave similarly to the order parameters in the phase transition instead of the Gauss-Bonnet coupling.

gr-qc↗

arXiv2021

Noether symmetry approach in non-minimal derivative coupling gravity

In this work, we examine solutions of the system of equations obtained by applying the Noether gauge symmetry (NGS) and its conserved quantity for the standard general relativity (GR) and the non-minimal derivative coupling (NMDC) cosmological model. We discover two salient features of the solutions. The first one is $a(t)\propto t^{1/3}$ for a kinetic-dominant phase which may emerge before inflationary period at very early time. The second one is a new form of scalar field $ϕ(t)$ govern by the exponential cosmological solution for GR and NMDC $ϕ_{\rm GR}(t)= \sqrt{c_{1}+c_{2}t+c_{3}e^{-λt}} $ and $ϕ_{\rm NMDC}(t)= \sqrt{c_{1}+c_{2}e^{-λ_{1}t}+c_{3}e^{-λ_{2}t}}$, respectively.

gr-qc↗

arXiv2021

Non-minimal coupled warm inflation with quantum-corrected self-interacting inflaton potential

In this work, we investigate the non-minimally coupled scenario in the context of warm inflation with quantum-corrected self-interacting potential. We transform the potential in the Jordan frame to the Einstein frame and consider a dissipation parameter of the form $Γ= C_{T}T$ with $C_T$ being a coupling parameter. We focus on the strong regime of which the interaction between inflaton and radiation fluid has been taken into account. We compute inflationary observables and constrain the parameters of our model using current Planck 2018 data. With the sizeable number of {\it e}-folds and proper choices of parameters, we discover that allowed values of $C_T$ lie in the range $0.014\lesssim C_{T}\lesssim 0.020$ in which the predictions are in good agreement with the latest Planck 2018 results at the $2\,σ$ confident level.

astro-ph.CO↗

arXiv2021

Cosmological dynamics of interacting dark energy and dark matter in viable models of f(R) gravity

In this work, we investigate the dynamics of the interacting dark energy and dark matter in viable models of $f(R)$ gravity by using a standard framework of dynamical system analysis. A simple form of the interacting dark energy $Q=3αHρ_{m}$ is used to study three viable models of $f(R)$ gravity which are consistent with local gravity constraints and satisfying conditions for the cosmological viability. As a result, we find that the fixed points are slightly modified from those obtained in the standard non-interacting analysis of $f(R)$ gravity proposed so far in the literature. In our models of adding this interaction, we find that the dynamical profiles of the universe in the viable $f(R)$ dark energy models are modified by the interaction term as well as their relevant model parameters. Moreover, our results yield the correct cosmological evolution with additional constraint parameter, $α$, from the interacting dark energy.

gr-qc↗