scholarly journals Quantum stability of aw<−1phase of cosmic acceleration

2007 ◽  
Vol 76 (4) ◽  
Author(s):  
E. O. Kahya ◽  
V. K. Onemli
Keyword(s):  
Cosmic Acceleration ◽  
Quantum Stability

scholarly journals Constraining the Swiss-Cheese IR-Fixed Point Cosmology with Cosmic Expansion

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 263
Author(s):  
Ayan Mitra ◽  
Vasilios Zarikas ◽  
Alfio Bonanno ◽  
Michael Good ◽  
Ertan Güdekli
Keyword(s):  
Fixed Point ◽  
Cosmological Constant ◽  
Cosmic Acceleration ◽  
Fine Tuning ◽  
Clusters Of Galaxies ◽  
Swiss Cheese ◽  
Coincidence Problem ◽  
Cosmological Expansion ◽  
Cosmic Evolution ◽  
Previous Assumption

A recent work proposed that the recent cosmic passage to a cosmic acceleration era is the result of the existence of small anti-gravity sources in each galaxy and clusters of galaxies. In particular, a Swiss-cheese cosmology model, which relativistically integrates the contribution of all these anti-gravity sources on a galactic scale has been constructed assuming the presence of an infrared fixed point for a scale dependent cosmological constant. The derived cosmological expansion provides an explanation for both the fine tuning and the coincidence problem. The present work relaxes the previous assumption on the running of the cosmological constant and allows for a generic scaling around the infrared fixed point. Our analysis reveals that, in order to produce a cosmic evolution consistent with the best ΛCDM model, the IR-running of the cosmological constant is consistent with the presence of an IR-fixed point.

Cosmic Acceleration: A Natural Remedy For Horizon and Flatness Problems

2005 ◽  
Vol 201 ◽  
pp. 488-489 ◽  
Author(s):  
Abhas. Mitra
Keyword(s):  
Initial Phase ◽  
Cosmic Acceleration ◽  
Natural Remedy

By assuming that the recently found cosmic acceleration is a genuine and ever present effect, we show that, the resultant modified Friedman model is free from the horizon and flatness problems; and there is no need to invoke the additional “inflationary” initial phase as a separate ingredient.

scholarly journals Multi-field dark energy: Cosmic acceleration on a steep potential

2021 ◽  
pp. 136427
Author(s):  
Yashar Akrami ◽  
Misao Sasaki ◽  
Adam R. Solomon ◽  
Valeri Vardanyan
Keyword(s):  
Dark Energy ◽  
Cosmic Acceleration

scholarly journals Cosmic acceleration data and bulk-brane energy exchange

2007 ◽  
Vol 76 (8) ◽  
Author(s):  
C. Bogdanos ◽  
S. Nesseris ◽  
L. Perivolaropoulos ◽  
K. Tamvakis
Keyword(s):  
Energy Exchange ◽  
Cosmic Acceleration ◽  
Acceleration Data

scholarly journals MODIFIED GRAVITY AS A COMMON CAUSE FOR COSMIC ACCELERATION AND FLAT GALAXY ROTATION CURVES

2012 ◽  
Vol 21 (11) ◽  
pp. 1242002 ◽  
Author(s):  
PRITI MISHRA ◽  
TEJINDER P. SINGH
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cosmic Acceleration ◽  
Accelerating Universe ◽  
Rotation Curves ◽  
Common Cause ◽  
Order Of Magnitude ◽  
Flat Rotation Curves ◽  
Acceleration Of The Universe ◽  
Galaxy Rotation Curves

Flat galaxy rotation curves and the accelerating Universe both imply the existence of a critical acceleration, which is of the same order of magnitude in both the cases, in spite of the galactic and cosmic length scales being vastly different. Yet, it is customary to explain galactic acceleration by invoking gravitationally bound dark matter, and cosmic acceleration by invoking a "repulsive" dark energy. Instead, might it not be the case that the flatness of rotation curves and the acceleration of the Universe have a common cause? In this essay we propose a modified theory of gravity. By applying the theory on galactic scales we demonstrate flat rotation curves without dark matter, and by applying it on cosmological scales we demonstrate cosmic acceleration without dark energy.

scholarly journals COSMIC ACCELERATION AND M THEORY COSMOLOGY

2004 ◽  
Vol 19 (13n16) ◽  
pp. 1093-1098 ◽  
Author(s):  
ISHWAREE P. NEUPANE
Keyword(s):  
Dark Energy ◽  
First Principles ◽  
Cosmic Acceleration ◽  
Curved Spaces ◽  
Short Overview ◽  
M Theory

This is a short overview of spatially flat (or open) four-dimensional accelerating cosmologies for some simple exponential potentials obtained by string or M theory compactification on some non-trivial curved spaces, which may lead to some striking results, e.g., the observed cosmic acceleration and the scale of the dark energy from first principles.

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