منابع مشابه
Curvature Quintessence
The issues of quintessence and cosmic acceleration can be discussed in the framework of higher order theories of gravity. We can define effective pressure and energy density directly connected to the Ricci scalar of curvature of a generic fourth order theory and then ask for the conditions to get an accelerated expansion. Exact accelerated expanding solutions can be achieved for several fourth ...
متن کاملCurvature and Torsion Quintessence
The issues of quintessence and cosmic acceleration can be discussed in the framework of higher order curvature and torsion theories of gravity. We can define effective pressure and energy density directly connected to the curvature or to the torsion fields and then ask for the conditions to get an accelerated expansion. Exact accelerated expanding solutions can be achieved for several fourth or...
متن کاملOn curvature coupling and quintessence fine-tuning
– We discuss the phenomenological model in which the potential energy of the quintessence field depends linearly on the energy density of the spatial curvature. We find that the pressure of the scalar field takes a different form when the potential of the scalar field also depends on the scale factor and the energy momentum tensor of the scalar field can be expressed as the form of a perfect fl...
متن کاملCurvature quintessence matched with observational data
Quintessence issues can be achieved by taking into account higher order curvature invariants into the effective action of gravitational field. Such an approach is naturally related to fundamental theories of quantum gravity which predict higher order terms in loop expansion of quantum fields in curved space-times. In this framework, we obtain a class of cosmological solutions which are fitted a...
متن کاملQuintessence Journals
This case report looks at a case of traumatic avulsion and subsequent apexification of a maxillary permanent incisor of a 6-year-old boy and a 10-year follow-up is reported. Treatment included apexification of the tooth with incomplete root formation using mineral trioxide aggregate and restoration of the immature root with a zirconia post and a coronal composite restoration. At the 10-year fol...
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ژورنال
عنوان ژورنال: International Journal of Modern Physics D
سال: 2002
ISSN: 0218-2718,1793-6594
DOI: 10.1142/s0218271802002025