Nonlocal cosmology.
نویسندگان
چکیده
We explore nonlocally modified models of gravity, inspired by quantum loop corrections, as a mechanism for explaining current cosmic acceleration. These theories enjoy two major advantages: they allow a delayed response to cosmic events, here the transition from radiation to matter dominance, and they avoid the usual level of fine-tuning; instead, emulating Dirac's dictum, the required large numbers come from the large time scales involved. Their solar system effects are safely negligible, and they may even prove useful to the black hole information problem.
منابع مشابه
Nonlocal teleparallel cosmology
Even though it is not possible to differentiate general relativity from teleparallel gravity using classical experiments, it could be possible to discriminate between them by quantum gravitational effects. These effects have motivated the introduction of nonlocal deformations of general relativity, and similar effects are also expected to occur in teleparallel gravity. Here, we study nonlocal d...
متن کاملReconstructing the Distortion Function for Nonlocal Cosmology
We consider the cosmology of modified gravity models in which Newton’s constant is distorted by a function of the inverse d’Alembertian acting on the Ricci scalar. We derive a technique for choosing the distortion function so as to fit an arbitrary expansion history. This technique is applied numerically to the case of ΛCDM cosmology, and the result agrees well with a simple hyperbolic tangent....
متن کاملSymmetries, Singularities and Integrability in Nonlinear Mathematical Physics and Cosmology
An overview is given of the interplay between symmetries, singularities and integrability and their uses in nonlinear problems arising in Mathematical Physics and Cosmology. A particularly important aspect is the role of nonlocal symmetries in deciding about integrability of complex nonlinear problems which do not apparently admit solutions in closed form. The need for a new approach to the evo...
متن کاملNonlocal Phenomena from Noncommutative Pre-Planckian Regime
A model unifying general relativity with quantum mechanics is further developed. It is based on a noncommutative geometry which supposedly modelled the universe in its pre-Planckian epoch. The geometry is totally nonlocal with no time and no space in their usual meaning. They emerge only in the transition process from the noncommutative epoch to the standard space-time physics. Observational as...
متن کاملEvolution of the Correlation Function for a Class of Processes Involving Nonlocal Self-replication
A large class of evolutionary processes can bemodeled by a rule that involves self-replication of some physical quantity with a nonlocal rescaling. We show that a class of such models is exactly solvable in the discrete as well as the continuum limit and can represent several physical situations, as varied as from the formation of galaxies in some cosmological models to growth of bacterial cult...
متن کامل0 20 40 71 v 1 2 2 A pr 2 00 2 Asymptotic states in brane cosmology with a nonlocal anisotropic stress
We investigate the dynamics of a Bianchi I brane Universe in the presence of a nonlocal anisotropic stress Pµν proportional to a " dark energy " U. Using this ansatz for the case U > 0 we prove that if a matter on a brane satisfies the equation of state p = (γ − 1)ρ with γ ≤ 4/3 then all such models isotropize. For γ > 4/3 anisotropic future asymptotic states are found. We also describe the pas...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Physical review letters
دوره 99 11 شماره
صفحات -
تاریخ انتشار 2007