منابع مشابه
Embedding Dark Energy in Supergravity
Dark energy[1] is one of the most intriguing puzzles of present day physics. When interpreted within the realm of General Relativity, its existence is linked to the presence of a weakly interacting fluid with a negative equation of state and a dominant energy density. The simplest possibility is of course a pure cosmological constant. A plausible alternative involves the presence of a scalar fi...
متن کاملDark energy versus modified gravity.
There is now strong observational evidence that the expansion of the Universe is accelerating. The standard explanation invokes an unknown "dark energy" component. But such scenarios are faced with serious theoretical problems, which has led to increased interest in models where instead general relativity is modified in a way that leads to the observed accelerated expansion. The question then a...
متن کاملDark Energy and Modified Gravity
Explanations of the late-time cosmic acceleration within the framework of general relativity are plagued by difficulties. General relativistic models are mostly based on a dark energy field with fine-tuned, unnatural properties. There is a great variety of models, but all share one feature in common – an inability to account for the gravitational properties of the vacuum energy, and a failure t...
متن کاملDark matter and dark energy as a effects of Modified
We explain the effect of dark matter (flat rotation curve) using modified gravitational dynamics. We investigate in this context a low energy limit of generalized general relativity with a nonlinear Lagrangian L ∝ R, where R is the (generalized) Ricci scalar and n is parameter estimated from SNIa data. We estimate parameter β in modified gravitational potential V (r) ∝ − 1 r (1 + ( r rc )). The...
متن کاملCuscuton Cosmology: Dark Energy meets Modified Gravity
In a companion paper [1], we have introduced a model of scalar field dark energy, Cuscuton, which can be realized as the incompressible (or infinite speed of sound) limit of a k-essence fluid. In this paper, we study how Cuscuton modifies the constraint sector of Einstein gravity. In particular, we study Cuscuton cosmology and show that even though Cuscuton can have an arbitrary equation of sta...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Modern Physics Letters A
سال: 2012
ISSN: 0217-7323,1793-6632
DOI: 10.1142/s0217732312502252