scholarly journals Emergent spacetime for quantum gravity

2016 ◽  
Vol 25 (13) ◽  
pp. 1645010 ◽  
Author(s):  
Hyun Seok Yang
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Quantum Gravity ◽  
Theoretical Physics ◽  
Hierarchy Problem ◽  
Cosmological Constant Problem ◽  
Cosmic Inflation ◽  
Thought Patterns ◽  
Emergent Spacetime ◽  
New Perspective

We emphasize that noncommutative (NC) spacetime necessarily implies emergent spacetime if spacetime at microscopic scales should be viewed as NC. In order to understand NC spacetime correctly, we need to deactivate the thought patterns that we have installed in our brains and taken for granted for so many years. Emergent spacetime allows a background-independent formulation of quantum gravity that will open a new perspective to resolve the notorious problems in theoretical physics such as the cosmological constant problem, hierarchy problem, dark energy, dark matter and cosmic inflation.

scholarly journals ACCELERATION AND DECELERATION IN THE CURVATURE-INDUCED PHANTOM MODEL OF THE LATE AND FUTURE UNIVERSE: COSMIC COLLAPSE AND ITS QUANTUM ESCAPE

2009 ◽  
Vol 18 (05) ◽  
pp. 865-887
Author(s):  
S. K. SRIVASTAVA ◽  
J. DUTTA
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Quantum Gravity ◽  
Cosmological Constant ◽  
Early Universe ◽  
High Energy ◽  
High Energy Density ◽  
Energy Models ◽  
Acceleration And Deceleration ◽  
The Universe

In this paper, the cosmology of the late and future universe is obtained from f(R) gravity with nonlinear curvature terms R2 and R3 (R is the Ricci scalar curvature). It is different from f(R) dark energy models where nonlinear curvature terms are taken as a gravitational alternative to dark energy. In the present model, neither linear nor nonlinear curvature terms are taken as dark energy. Rather, dark energy terms are induced by curvature terms and appear in the Friedmann equation derived from f(R) gravitational equations. This approach has an advantage over f(R) dark energy models in three ways: (i) results are consistent with WMAP observations, (ii) dark matter is produced from the gravitational sector and (iii) the universe expands as ~ t2/3 during dominance of the curvature-induced dark matter, which is consistent with the standard cosmology. Curvature-induced dark energy mimics phantom and causes late acceleration. It is found that transition from matter-driven deceleration to acceleration takes place at the redshift 0.36 at time 0.59 t0 (t0 is the present age of the universe). Different phases of this model, including acceleration and deceleration during the phantom phase, are investigated. It is found that expansion of the universe will stop at the age of 3.87 t0 + 694.4 kyr. After this epoch, the universe will contract and collapse by the time of 336.87 t0 + 694.4 kyr. Further, it is shown that cosmic collapse obtained from classical mechanics can be avoided by making quantum gravity corrections relevant near the collapse time due to extremely high energy density and large curvature analogous to the state of the very early universe. Interestingly, the cosmological constant is also induced here; it is extremely small in the classical domain but becomes very high in the quantum domain. This result explains the largeness of the cosmological constant in the early universe due to quantum gravity effects during this era and its very low value in the present universe due to negligible quantum effect in the late universe.

scholarly journals DARK ENERGY AND EMERGENT SPACETIME

2011 ◽  
Vol 01 ◽  
pp. 266-271
Author(s):  
HYUN SEOK YANG
Keyword(s):  
Dark Energy ◽  
Symplectic Geometry ◽  
Cosmological Constant Problem ◽  
Geometric Framework ◽  
Emergent Gravity ◽  
Flat Spacetime ◽  
Darboux Theorem ◽  
Noncommutative Spacetime ◽  
Emergent Spacetime ◽  
Planck Energy

A natural geometric framework of noncommutative spacetime is symplectic geometry rather than Riemannian geometry. The Darboux theorem in symplectic geometry then admits a novel form of the equivalence principle such that the electromagnetism in noncommutative spacetime can be regarded as a theory of gravity. Remarkably the emergent gravity reveals a noble picture about the origin of spacetime, dubbed as emergent spacetime, which is radically different from any previous physical theory all of which describe what happens in a given spacetime. In particular, the emergent gravity naturally explains the dynamical origin of flat spacetime, which is absent in Einstein gravity: A flat spacetime is not free gratis but a result of Planck energy condensation in a vacuum. This emergent spacetime picture, if it is correct anyway, turns out to be essential to resolve the cosmological constant problem, to understand the nature of dark energy and to explain why gravity is so weak compared to other forces.

scholarly journals Entropic Information Theory: Formulae and Quantum Gravity, Bits from bit

2021 ◽  
Author(s):  
olivier denis
Keyword(s):  
Information Theory ◽  
General Relativity ◽  
Dark Matter ◽  
Quantum Mechanics ◽  
Dark Energy ◽  
Quantum Gravity ◽  
Planck Scale ◽  
Basic Structure ◽  
Mathematical Framework ◽  
Information Framework

We show here that entropic information is capable of unifying all aspects of the universe at all scales in a coherent and global theoretical mathematical framework materialized by entropic information framework, theory and formulas, where dark matter, dark energy and gravity are truly informationals processes and where information is code and code is what creates the process, it is itself the process. Mass, energy and movement of information are respectively dark matter, dark energy, and gravity. Here, we reconcile general relativity and quantum mechanics by introducing quantum gravity for the Planckian scale. The formulas of entropic information are expressed in natural units, physical units of measurement based only on universal constants, constants, which refer to the basic structure of the laws of physics: C and G are part of the structure of space-time in general relativity, and h captures the relationship between energy and frequency that is the basis of quantum mechanics. Here we show that entropic information formulas are able to present entropic information in various unifying aspects and introduce gravity at the Planck scale. We prove that Entropic information theory is thus building the bridge between general relativity and quantum mechanics

Relational Blockworld Approach to Unification and Quantum Gravity

2018 ◽  
Author(s):  
Michael Silberstein ◽  
W.M. Stuckey ◽  
Timothy McDevitt
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Quantum Gravity ◽  
Particle Physics ◽  
Lattice Gauge Theory ◽  
Galactic Rotation ◽  
Microwave Background ◽  
Angular Power Spectrum ◽  
Lattice Gauge ◽  
Main Thread

The main thread of chapter 6 prompts the need for quantum gravity (QG) and introduces the RBW approach to QG, unification in particle physics, dark matter, and dark energy. The details of RBW’s modified Regge calculus and modified lattice gauge theory approaches are conveyed conceptually in the main thread. The RBW fits of galactic rotation curves, galactic cluster mass profiles, the angular power spectrum of the cosmic microwave background, and the Union2.1 supernova data associated with dark matter and dark energy are in Foundational Physics for Chapter 6. In Philosophy of Physics for Chapter 6, RBW’s taxonomic location with respect to other discrete approaches to QG is detailed and it is argued that the search for QG is stymied by the dynamical paradigm across the board. Further, it is maintained that an adynamical global constraint as the basis for QG in the block universe provides a self-vindicating unification of physics.

scholarly journals Applications of Canonical Quantum Gravity to Cosmology

Symmetry ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1005
Author(s):  
Claus Gerhardt
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Quantum Gravity ◽  
Canonical Quantum Gravity ◽  
Canonical Quantum

We applied quantum gravitational results to spatially unbounded Friedmann universes and tried to answer some questions related to dark energy, dark matter, inflation, and the missing antimatter.

scholarly journals Modified inertial mass from information loss

2017 ◽  
Vol 32 (28) ◽  
pp. 1750148 ◽  
Author(s):  
Michael E. McCulloch ◽  
Jaume Giné
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Inertial Mass ◽  
Information Loss ◽  
Cosmic Acceleration ◽  
Mass Energy ◽  
Cosmological Constant Problem ◽  
Hubble Horizon ◽  
Discrete Manner ◽  
Very High

A modification of inertia (called MiHsC or quantized inertia) has been proposed that assumes that inertia is caused by Unruh radiation, and that this radiation is made inhomogeneous in space by either Rindler horizons caused by acceleration or the distant Hubble horizon. The former predicts the standard inertial mass, and the latter predicts galaxy rotation without dark matter and cosmic acceleration without dark energy. It is proposed here that this model can be derived in an alternative way by assuming that the sum of mass (M), energy (E) and the information content of horizons (I) is conserved (EMI) so that mass–energy is released in a discrete manner when the area of a Rindler horizon reduces. This model could be tested by looking for the quantization of inertial mass and acceleration at very high accelerations, and may provide an explanation for the cosmological constant problem.

scholarly journals Entropic Information Theory: Formulae and Quantum Gravity Bits from Bit

2021 ◽  
pp. 23-30
Author(s):  
Olivier Denis
Keyword(s):  
Information Theory ◽  
General Relativity ◽  
Dark Matter ◽  
Quantum Mechanics ◽  
Dark Energy ◽  
Quantum Gravity ◽  
Planck Scale ◽  
Basic Structure ◽  
Mathematical Framework ◽  
Information Framework

We show here that entropic information is capable of unifying all aspects of the universe at all scales in a coherent and global theoretical mathematical framework materialized by entropic information framework, theory and formulas, where dark matter, dark energy and gravity are truly informationals processes and where information is code and code is what creates the process, it is itself the process. Mass, energy and movement of information are respectively dark matter, dark energy, and gravity. Here, we reconcile general relativity and quantum mechanics by introducing quantum gravity for the Planckian scale. The formulas of entropic information are expressed in natural units, physical units of measurement based only on universal constants, constants, which refer to the basic structure of the laws of physics:  C and G are part of the structure of space-time in general relativity, and h captures the relationship between energy and frequency that is the basis of quantum mechanics. Here we show that entropic information formulas are able to present entropic information in various unifying aspects and introduce gravity at the Planck scale. We prove that Entropic information theory is thus building the bridge between general relativity and quantum mechanics

New species of fermions and bosons, cosmological constant problem and a farewell to spin–statistics theorem

2021 ◽  
Author(s):  
Dharam Vir Ahluwalia
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Degrees Of Freedom ◽  
Zero Point ◽  
Direct Argument ◽  
Hierarchy Problem ◽  
Cosmological Constant Problem ◽  
Point Energy ◽  
Net Zero ◽  
Astronomical Time

If dark matter exists in the form of ultralight fermionic and bosonic species, then (a) it can accelerate evaporation of astrophysical black holes to the extent that their lifetimes can be reduced to astronomical time scales, a and (b) if there are extremely large number of such species it has the potential to solve the hierarchy problem [H. Davoudiasl, P. B. Denton and D. A. McGady, Phys. Rev. D 103 (2021) 055014; G. Dvali, Fortschr. Phys. 58 (2010) 528]. Here, we put forward a proposal that darkness of many of these new particles is natural, and in addition, the net zero point energy of the fermions exactly cancels that coming from the new bosons. The needed fermion–boson equality, and matching the fermion–boson degrees of freedom, comes about naturally. A very direct argument that allows the departure from the spin–statistics theorem is presented.

Einstein’s General Theory of Relativity and the Development of Modified Theories of Gravitation

2020 ◽  
Vol 29 (11) ◽  
pp. 2-9
Author(s):  
Bogeun GWAK, ◽  
Bum-Hoon LEE ◽  
Wonwoo LEE
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Dark Energy ◽  
General Theory ◽  
Quantum Gravity ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Theory Of Gravitation ◽  
Wave Dark Matter ◽  
Theories Of Gravitation

We briefly review both Einstein’s general theory of relativity and the development of modified theories of gravitation with theoretical and observational motivations. For this, we discuss the theoretical properties and weaknesses of general relativity. We also mention attempts that have been made to develop the theory of quantum gravity. The recent detections of a gravitational wave, dark matter, and dark energy have opened new windows into astrophysics, as well as cosmology, through which tests to determine the theory of gravitation that best describes our Universe would be interesting. Most of all, note that we cannot clearly describe our Universe, including dark matter and dark energy, with standard particle models and the general theory of relativity. In these respects, we must be open-minded and study all possible aspects.

scholarly journals Entropic Information Theory: Formulae and Quantum Gravity, Bits from Bit

2021 ◽  
Author(s):  
olivier denis
Keyword(s):  
Information Theory ◽  
General Relativity ◽  
Dark Matter ◽  
Quantum Mechanics ◽  
Dark Energy ◽  
Quantum Gravity ◽  
Planck Scale ◽  
Basic Structure ◽  
Mathematical Framework ◽  
Information Framework

We show here that entropic information is capable of unifying all aspects of the universe at all scales in a coherent and global theoretical mathematical framework materialized by entropic information framework, theory and formulas, where dark matter, dark energy and gravity are truly informationals processes and where information is code and code is what creates the process, it is itself the process. Mass, energy and movement of information are respectively dark matter, dark energy, and gravity. Here, we reconcile general relativity and quantum mechanics by introducing quantum gravity for the Planckian scale. The formulas of entropic information are expressed in natural units, physical units of measurement based only on universal constants, constants, which refer to the basic structure of the laws of physics: C and G are part of the structure of space-time in general relativity, and h captures the relationship between energy and frequency that is the basis of quantum mechanics. Here we show that entropic information formulas are able to present entropic information in various unifying aspects and introduce gravity at the Planck scale. We prove that Entropic information theory is thus building the bridge between general relativity and quantum mechanics

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