ترغب بنشر مسار تعليمي؟ اضغط هنا

Potentials of Coupled Quintessence Based on a Dilaton

73   0   0.0 ( 0 )
 نشر من قبل Zengguang Huang
 تاريخ النشر 2006
  مجال البحث
والبحث باللغة English




اسأل ChatGPT حول البحث

In this paper, we regard dilaton in Weyl-scaled induced gravitational theory as coupled Quintessence, which is called DCQ model by us. Parametrization of the dark energy model is a good method by which we can construct the scalar potential directly from the effective equation of state function $omega_sigma(z)$ describing the properties of the dark energy. Applying this method to the DCQ model, we consider four parametrizations of $omega(z)$ and investigate the features of the constructed DCQ potentials, which possess two different evolutive behaviors called O mode and E mode. Lastly, we comprise the results of the constructed DCQ model with those of quintessence model numerically.

قيم البحث

اقرأ أيضاً

78 - Z. G. Huang , H. Q. Lu , W. Fang 2006
Based on dilatonic dark energy model, we consider two cases: dilaton field with positive kinetic energy(coupled quintessence) and with negative kinetic energy(phantom). In the two cases, we investigate the existence of attractor solutions which corre spond to an equation of state parameter $omega=-1$ and a cosmic density parameter $Omega_sigma=1$. We find that the coupled term between matter and dilaton cant affect the existence of attractor solutions. In the Mexican hat potential, the attractor behaviors, the evolution of state parameter $omega$ and cosmic density parameter $Omega$, are shown mathematically. Finally, we show the effect of coupling term on the evolution of $X(frac{sigma}{sigma_0})$ and $Y(frac{dot{sigma}}{sigma^2_0})$ with respect to $N(lna)$ numerically.
125 - Z. G. Huang , H. Q. Lu , W. Fang 2006
In this paper, we regard dilaton in Weyl-scaled induced gravitational theory as a coupled quintessence. Based on this consideration, we investigate the dilaton coupled quintessence(DCQ) model in $omega-omega$ plane, which is defined by the equation o f state parameter for the dark energy and its derivative with respect to $N$(the logarithm of the scale factor $a$). We find the scalar field equation of motion in $omega-omega$ plane, and show mathematically the property of attractor solutions which correspond to $omega_sigmasim-1$, $Omega_sigma=1$. Finally, we find that our model is a tracking one which belongs to freezing type model classified in $omega-omega$ plane.
254 - J. Horne , G. Horowitz 1992
We investigate charged black holes coupled to a massive dilaton. It is shown that black holes which are large compared to the Compton wavelength of the dilaton resemble the Reissner-Nordstrom solution, while those which are smaller than this scale re semble the massless dilaton solutions. Black holes of order the Compton wavelength of the dilaton can have wormholes outside the event horizon in the string metric. Unlike all previous black hole solutions, nearly extremal and extremal black holes (of any size) repel each other. We argue that extremal black holes are quantum mechanically unstable to decay into several widely separated black holes. We present analytic arguments and extensive numerical results to support these conclusions.
We proceed to study a (1+1)-dimensional dilaton gravity system with a hyperbolic dilaton potential. Introducing a couple of new variables leads to two copies of Liouville equations with two constraint conditions. In particular, in conformal gauge, th e constraints can be expressed with Schwarzian derivatives. We revisit the vacuum solutions in light of the new variables and reveal its dipole-like structure. Then we present a time-dependent solution which describes formation of a black hole with a pulse. Finally, the black hole thermodynamics is considered by taking account of conformal matters from two points of view: 1) the Bekenstein-Hawking entropy and 2) the boundary stress tensor. The former result agrees with the latter one with a certain counter-term.
The minimal Starobinsky supergravity with the inflaton (scalaron) and the goldstino in a massive vector supermultiplet is coupled to the dilaton-axion chiral superfield with the no-scale Kahler potential and a superpotential. The Kachru-Kallosh-Linde -Trivedi (KKLT)-type mechanism in the presence of a constant term in the superpotential is applied to stabilize the dilaton/axion during inflation, and it is shown to lead to an instability. The instability is cured by adding the alternative Fayet-Iliopoulos (FI) term that does not lead to the gauged $R$-symmetry. Other stabilization mechanisms, based on the Wess-Zumino (WZ)-type superpotential, are also studied in the presence of the FI term. A possible connection to a D3-brane is briefly discussed too.
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