A bridge between unified cosmic history by f(R)-gravity and BIonic system

Abstract

Recently, the cosmological deceleration-acceleration transition redshift in f (R) gravity has been considered in order to address consistently the problem of cosmic evolution. It is possible to show that the deceleration parameter changes sign at a given redshift according to observational data. Furthermore, a f (R) gravity cosmological model can be constructed in brane-antibrane system starting from the very early universe and accounting for the cosmological redshift at all phases of cosmic history, from inflation to late time acceleration. Here we propose a f (R) model where transition redshifts correspond to inflation-deceleration and deceleration-late time acceleration transitions starting froma BIon system. At the point where the universe was born, due to the transition of k black fundamental strings to the BIon configuration, the redshift is approximately infinity and decreases with reducing temperature (z ∼ T 2 ). The BIon is a configuration in flat space of a universe-brane and a parallel anti-universe-brane connected by a wormhole. This wormhole is a channel for flowing energy from extra dimensions into our universe, occurring at inflation and decreasing with redshift as z ∼ T 4+1/7 . Dynamics consists with the fact that the wormhole misses its energy and vanishes as soon as inflation ends and deceleration begins. Approaching two universe branes together, a tachyon is originated, it grows up and causes the formation of a wormhole. We show that, in the framework of f (R) gravity, the cosmological redshift depends on the tachyonic potential and has a significant decrease at deceleration-late time acceleration transition point (z ∼ T 2/3 ). As soon as today acceleration approaches, the redshift tends to zero and the cosmological model reduces to the standard ΛCDM cosmology.PACS numbers: 98.80.-k, 95.35.+d, 95.36.+x

Modeling the Electron Transport in Nanostructures by Using the Concept of BIons in M-theory

“…In fact, by increasing temperature, photons disconnect from each other, wormhole like tunnel disappears and the energy of (13) can be reduced to (52). To show this, we substitute (14) in (13) and obtain [12][13][14][15][16]20]:…”

“…Now, we can show that there is a direct relation between two theories. To this end, let us rewrite the general form of the BIonic action as [9,20,21]:…”

“…If we have only a pair of electrons and ignore all other electrons, the nonlinear electrodynamics transit to linear one which is given by following equation [12][13][14][15][16]20]:…”

“…It is possible to show that (54) reduces to Lagrangian of f (R) gravity by using the following mappings [20]:…”

Phantom fluid supporting traversable wormholes in alternative gravity with extra material terms

“…Once these alternative paths have shown good results (besides, 5,6 check, for instance, [9][10][11][12][13] ), in this paper we will present the solution and behaviour of WHs under the f (R, T ) gravitational action, 14 for which R is the Ricci scalar and T is the trace of the energy-momentum tensor. Using the appropriate metric for the static WH, the importance of the redshift and shape functions will be observed on different cases, analysing the possibility of generating a traversable WH.…”