314 research outputs found

### Emergence of Cosmic Space and Minimal Length in Quantum Gravity

An emergence of cosmic space has been suggested by Padmanabhan in
[arXiv:1206.4916]. This new interesting approach argues that the expansion of
the universe is due to the difference between the number of degrees of freedom
on a holographic surface and the one in the emerged bulk. In this paper, we
derive, using emergence of cosmic space framework, the general dynamical
equation of FRW universe filled with a perfect fluid by considering a generic
form of the entropy as a function of area. Our derivation is considered as a
generalization of emergence of cosmic space with a general form of entropy. We
apply our equation with higher dimensional spacetime and derive modified
Friedmann equation in Gauss-Bonnet gravity. We then apply our derived equation
with the corrected entropy-area law that follows from Generalized Uncertainty
Principle (GUP) and derive a modified Friedmann equations due to the GUP. We
then derive the modified Raychaudhuri equation due to GUP in emergence of
cosmic space framework and investigate it using fixed point method. Studying
this modified Raychaudhuri equation leads to non-singular solutions which may
resolve singularities in FRW universe.Comment: 10 pages, revtex4, 1 figure, to match published version in PL

### Planck-Scale Corrections to Friedmann Equation

Recently, Verlinde proposed that gravity is an emergent phenomenon which
originates from an entropic force. In this work, we extend Verlinde's proposal
to accommodate generalized uncertainty principles (GUP), which are suggested by
some approaches to \emph{quantum gravity} such as string theory, black hole
physics and doubly special relativity (DSR). Using Verlinde's proposal and two
known models of GUPs, we obtain modifications to Newton's law of gravitation as
well as the Friedmann equation. Our modification to the Friedmann equation
includes higher powers of the Hubble parameter which is used to obtain a
corresponding Raychaudhuri equation. Solving this equation, we obtain a leading
Planck-scale correction to Friedmann-Robertson-Walker (FRW) solutions for the
$p=\omega \rho$ equation of state.Comment: 15 pages, no figure, to appear in Central Eur.J.Phys. arXiv admin
note: text overlap with arXiv:1301.350

### Modified Newton's Law of Gravitation Due to Minimal Length in Quantum Gravity

A recent theory about the origin of the gravity suggests that the gravity is
originally an entropic force. In this work, we discuss the effects of
generalized uncertainty principle (GUP) which is proposed by some approaches to
quantum gravity such as string theory, black hole physics and doubly special
relativity theories (DSR), on the area law of the entropy. This leads to a
$\sqrt{Area}$-type correction to the area law of entropy which imply that the
number of bits $N$ is modified. Therefore, we obtain a modified Newton's law of
gravitation. Surprisingly, this modification agrees with different sign with
the prediction of Randall-Sundrum II model which contains one uncompactified
extra dimension. Furthermore, such modification may have observable
consequences at length scales much larger than the Planck scale.Comment: 12 pages, no figures, references adde

- …