ترغب بنشر مسار تعليمي؟ اضغط هنا

From inflation to recent cosmic acceleration: The fermionic Elko field driving the evolution of the universe

205   0   0.0 ( 0 )
 نشر من قبل Saulo Pereira H
 تاريخ النشر 2017
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

In this paper we construct the complete evolution of the universe driven by the mass dimension one dark spinor called Elko, starting with inflation, passing by the matter dominated era and finishing with the recent accelerated expansion. The dynamic of the fermionic Elko field with a symmetry breaking type potential can reproduce all phases of the universe in a natural and elegant way. The dynamical equations in general case and slow roll conditions in the limit $Hll m_{pl}$ are also presented for the Elko system. Numerical analysis for the number of e-foldings during inflation, energy density after inflation and for present time and also the actual size of the universe are in good agreement with the standard model of cosmology. An interpretation of the inflationary phase as a result of Pauli exclusion principle is also possible if the Elko field is treated as an average value of its quantum analogue.



قيم البحث

اقرأ أيضاً

We study the inflationary period driven by a fermionic field which is non-minimally coupled to gravity in the context of the constant-roll approach. We consider the model for a specific form of coupling and perform the corresponding inflationary anal ysis. By comparing the result with the Planck observations coming from CMB anisotropies, we find the observational constraints on the parameters space of the model and also the predictions the model. We find that the values of $r$ and $n_{s}$ for $-1.5<betaleq-0.9$ are in good agreement with the observations when $|xi|=0.1$ and $N=60$.
We studied bulk viscosity in the modified $f(Q,T)$ gravity theory formalism, where $Q$ represents the non-metricity and $T$ denotes the trace of energy-momentum tensor within a flat Friedmann-Lema^{i}tre-Robertson-Walker metric (FLRW). We consider th e effective equation of state, which includes a bulk viscosity term explicitly. We find the exact solutions relating to bulk viscosity by assuming a specific form of $f(Q,T)=alpha Q+beta T$, where $alpha$ and $beta$ are constants. Furthermore, we constrained our model with revised Hubble datasets consisting of 57 data points and newly published Pantheon samples with 1048 points to obtain the best fitting values of the model parameters. Our model is found to be in good agreement with observations. Furthermore, we analysed the cosmological behavior of the density parameter, the equation of state (EoS) parameter ($omega$), and the deceleration parameter ($q$). The universe appears to be evolving from a decelerated to an accelerated phase. The EoS parameter is further found to be in the quintessence phase, indicating that the universe is accelerating. We can deduce that the accumulation of bulk viscosity as effective dark energy is responsible for the current accelerated expansion of the universe.
113 - Supratik Pal 2008
A new idea of deriving a cosmological term from an underlying theory has been proposed in order to explain the expansion history of the universe. We obtain the scale factor with this derived cosmological term and demonstrate that it reflects all the characteristics of the expanding universe in different era so as to result in a transition from inflation to late acceleration through intermediate decelerating phases by this single entity. We further discuss certain observational aspects of this paradigm.
We show that in the realm of general relativity a non minimal coupling between the electromagnetic and the gravitational fields may produce an era of accelerated expansion.
This paper study the evolution of the universe filled with a neutral mass dimension one fermionic field, sometimes called Elko. The numerical analysis of the coupled system of equations furnish a scale factor growth and energy density evolution that correctly reproduces the inflationary phase of the universe. After that, supposing a mechanism of energy transference to ordinary matter, the initial conditions generated after inflation drives the radiation dominated phase and also the subsequent dark matter evolution, since the Elko field is a good dark matter candidate. The energy density of the field at the end of inflation, at the end of radiation phase and for present time are in agreement to the standard model estimates. The analysis was performed with a potential containing a quadratic mass term plus a quartic self-interaction term, which follows naturally from the theory of mass dimension one fermions. It is interesting to notice that inflation occurs when the field makes a kind of transition around the Planck mass scale. The number of e-foldings during inflation was found to be strongly dependent on the initial conditions of the Elko field, as occurs in chaotic inflationary models. An upper mass limit for Elko field has been obtained as $m<10^9$GeV. A possible interpretation of both inflationary phase and recent cosmic acceleration as a consequence of a kind of Pauli exclusion principle is presented at the end.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا