اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدDeflation of Vacuum Energy During Inflation Due to Bulk-Brane Interaction
93
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We consider a brane world inflationary model in which inflation is driven by dynamics of a self-interacting scalar field living in the five-dimensional bulk. The scalar field is non-minimally coupled to matter fields on the brane and acts as an inflaton which induces a slow-roll inflation. We show that although the Friedmann equation is modified at early times due to effects of the extra dimension, the slow-roll condition is the same as that of the four-dimensional case. Due to the non-minimal coupling of matter with the bulk scalar, there is an energy transfer between the two components. We investigate the conditions under which the direction of this energy transfer can be from matter onto the bulk scalar. There are at least two advantages in this case: 1) It establishes a mechanism by which a large effective cosmological term on the brane is deflated during the inflation period. 2) The energy flow onto the bulk inflaton gives a more strongly damped evolution of the scalar field in the slow-roll region for a given potential. We then show that our results are supported by numerical estimations with quadratic and exponential potentials.
قيم البحث
اقرأ أيضاً
We investigate the role of bulk viscous pressure on the warm inflationary modified Chaplygin gas in brane-world framework in the presence of standard scalar field. We assume the intermediate inflationary scenario in strong dissipative regime and cons
tructed the inflaton, potential, entropy density, slow-roll parameters, scalar and tensor power spectra, scalar spectral index and tensor-to-scalar ratio. We develop various trajectories such as $n_s - N$, $n_s - r$ and $n_s - alpha_s$ (where $n_s$ is the spectral index, $alpha_s$ is the running of spectral index, $N$ is the number of e-folds and $r$ is tensor-to-scalar ratio) for variable as well as constant dissipation and bulk viscous coefficients at high dissipative regime. It is interesting to remark here that our results of these parameters are compatible with recent observational data such as WMAP $7+9$, BICEP$2$ and Planck data.
We compute the renormalized expectation value of the square of a massless, conformally coupled, quantum scalar field on the brane of a higher-dimensional black hole. Working in the AADD brane-world scenario, the extra dimensions are flat and we assum
e that the compactification radius is large compared with the size of the black hole. The four-dimensional on-brane metric corresponds to a slice through a higher-dimensional Schwarzschild-Tangherlini black hole geometry and depends on the number of bulk space-time dimensions. The quantum scalar field is in a thermal state at the Hawking temperature. An exact, closed-form expression is derived for the renormalized expectation value of the square of the quantum scalar field on the event horizon of the black hole. Outside the event horizon, this renormalized expectation value is computed numerically. The answer depends on the number of bulk space-time dimensions, with a magnitude which increases rapidly as the number of bulk space-time dimensions increases.
We show that in the vacuum inflation model, the gravitational baryogenesis mechanism will produce the baryon asymmetry. We analyze the evolution of entropy and baryon number in the vacuum inflation model. The comparison between dilution speed and the
chemical potential may give a natural interpretation for decouple temperature of the gravitational baryogenesis interaction. From the result, the mechanism can give acceptable baryon-to-entropy ratio in the vacuum inflation model.
Current universe (assumed here to be normal matter on the brane) is pressureless from observations. In this case the energy condition is $rho_0geq0$ and $p_0=0$. By using this condition, brane models can be distinguished. Then, assuming arbitrary com
ponent of matter in DGP model, we use four known energy conditions to study the matter on the brane. If there is nonnormal matter or energy (for example dark energy with $w<-1/3$) on the brane, the universe is accelerated.
We develop the formalism for computing gravitational corrections to vacuum decay from de Sitter space as a sub-Planckian perturbative expansion. Non-minimal coupling to gravity can be encoded in an effective potential. The Coleman bounce continuously
deforms into the Hawking-Moss bounce, until they coincide for a critical value of the Hubble constant. As an application, we reconsider the decay of the electroweak Higgs vacuum during inflation. Our vacuum decay computation reproduces and improves bounds on the maximal inflationary Hubble scale previously computed through statistical techniques.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
