اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدQuadratic chaotic inflation with a logarithmic-corrected mass
53
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We consider a simple modification of quadratic chaotic inflation. We add a logarithmic correction to the mass term, and find that this model can be consistent with the latest cosmological observations such as the Planck 2018 data, in combination with the BICEP2/Keck Array and the baryon acoustic oscillation data. Since the model predicts the lower limit for the tensor-to-scalar ratio r for the present allowed values of the spectral index n_s, it could be tested by the cosmic microwave background polarization observation in the near future. In addition, we consider higher-order logarithmic corrections. Interestingly, we observe that the scalar spectral index n_s and r stay in rather a narrow region of the parameter space. Moreover, they reside in a completely different region from that for the logarithmic corrections to the quartic coupling. Therefore, future observations may distinguish which kind of corrections should be included, or even single out the form of the interactions.
قيم البحث
اقرأ أيضاً
In this paper we investigate the inflationary phenomenology of an Einstein-Gauss-Bonnet theory with the extension of a logarithmic modified $f(R)$ gravity, compatible with the GW170817 event. The main idea of our work is to study different results fo
r an almost linear Ricci scalar through logarithmic corrections and examine whether such model is viable. First of all, the theoretical framework under slow-roll evolution of the scalar field is presented and also developed the formalism of the constant-roll evolution making predictions for the non- Gaussianities of the models is developed , since the constant-roll evolution is known to enhance non-Gaussianities. As shown, the non-Gaussianities are of the order $mathcal{O}sim(10^{-1})$. Furthermore, the slow-roll indices and the observational indices of inflation, are calculated for several models of interest. As demonstrated, the phenomenological viability of the models at hand is achieved for a wide range of the free parameters and the logarithmic term has a minor contribution to numerical calculations, as expected.
Primordial blackholes formed in the early Universe via gravitational collapse of over-dense regions may contribute a significant amount to the present dark matter relic density. Inflation provides a natural framework for the production mechanism of p
rimordial blackholes. For example, single field inflation models with a fine-tuned scalar potential may exhibit a period of ultra-slow-roll, during which the curvature perturbation may be enhanced to become seeds of the primordial blackholes formed as the corresponding scales reenter the horizon. In this work we propose an alternative mechanism for the primordial blackhole formation. We consider a model in which a scalar field is coupled to the Gauss-Bonnet term, and show that primordial blackholes may be seeded when a scalar potential term and the Gauss-Bonnet coupling term are nearly balanced. Large curvature perturbation in this model not only leads to the production of primordial blackholes but it also sources gravitational waves at the second order. We calculate the present density parameter of the gravitational waves and discuss the detectability of the signals by comparing them with sensitivity bounds of future gravitational wave experiments.
We study chaotic inflation in the context of modified gravitational theories. Our analysis covers models based on (i) a field coupling $omega(phi)$ with the kinetic energy $X$ and a nonmimimal coupling $zeta phi^{2} R/2$ with a Ricci scalar $R$, (ii)
Brans-Dicke (BD) theories, (iii) Gauss-Bonnet (GB) gravity, and (iv) gravity with a Galileon correction. Dilatonic coupling with the kinetic energy and/or negative nonminimal coupling are shown to lead to compatibility with observations of the Cosmic Microwave Background (CMB) temperature anisotropies for the self-coupling inflaton potential $V(phi)=lambda phi^{4}/4$. BD theory with a quadratic inflaton potential, which covers Starobinskys $f(R)$ model $f(R)=R+R^{2}/(6M^{2})$ with the BD parameter $omega_{BD}=0$, gives rise to a smaller tensor-to-scalar ratio for decreasing $omega_{BD}$. In the presence of a GB term coupled to the field $phi$, we express the scalar/tensor spectral indices $n_{s}$ and $n_{t}$ as well as the tensor-to-scalar ratio $r$ in terms of two slow-roll parameters and place bounds on the strength of the GB coupling from the joint data analysis of WMAP 7yr combined with other observations. We also study the Galileon-like self-interaction $Phi(phi) X squarephi$ with exponential coupling $Phi(phi) propto e^{muphi}$. Using a CMB likelihood analysis we put bounds on the strength of the Galileon coupling and show that the self coupling potential can in fact be made compatible with observations in the presence of the exponential coupling with $mu>0$.
A coherently oscillating real scalar field with potential shallower than quadratic one fragments into spherical objects called I-balls. We study the I-ball formation for logarithmic potential which appears in many cosmological models. We perform latt
ice simulations and find that the I-balls are formed when the potential becomes dominated by the quadratic term. Furthermore, we estimate the I-ball profile assuming that the adiabatic invariant is conserved during formation and obtain the result that agrees to the numerical simulations.
We analyze dynamical properties of the logarithmic Schr{o}dinger equation under a quadratic potential. The sign of the nonlinearity is such that it is known that in the absence of external potential, every solution is dispersive, with a universal asy
mptotic profile. The introduction of a harmonic potential generates solitary waves, corresponding to generalized Gaussons. We prove that they are orbitally stable, using an inequality related to relative entropy, which may be thought of as dual to the classical logarithmic Sobolev inequality. In the case of a partial confinement, we show a universal dispersive behavior for suitable marginals. For repulsive harmonic potentials, the dispersive rate is dictated by the potential, and no universal behavior must be expected.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
