scholarly journals Predicting Planck Scale and Newtonian Constant from a Yang-Mills Gauge Theory: 1- and 2-Loop Estimates

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Rodrigo F. Sobreiro ◽  
Anderson A. Tomaz
Keyword(s):  
Gauge Theory ◽  
Cosmological Constant ◽  
Planck Scale ◽  
Cosmological Constant Problem ◽  
Emergent Gravity ◽  
Yang Mills ◽  
Dimensional Spacetime ◽  
Newtonian Constant

Recently, a model for an emergent gravity based onSO(5)Yang-Mills action in Euclidian 4-dimensional spacetime was proposed. In this work we provide some 1- and 2-loop computations and show that the model can accommodate suitable predicting values for the Newtonian constant. Moreover, it is shown that the typical scale of the expected transition between the quantum and the geometrodynamical theory is consistent with Planck scale. We also provide a discussion on the cosmological constant problem.

EMERGENT GRAVITY AND GAUGE THEORY FROM MATRIX MODELS

2009 ◽  
Vol 24 (15) ◽  
pp. 2866-2876 ◽  
Author(s):  
HAROLD STEINACKER
Keyword(s):  
Gauge Theory ◽  
Cosmological Constant ◽  
Matrix Models ◽  
Classical Limit ◽  
Recent Progress ◽  
Gauge Fields ◽  
Cosmological Constant Problem ◽  
Emergent Gravity ◽  
Yang Mills ◽  
Effective Gravity

Matrix models of Yang-Mills type induce an effective gravity theory on 4-dimensional branes, which are considered as models for dynamical space-time. We review recent progress in the understanding of this emergent gravity. The metric is not fundamental but arises effectively in the semi-classical limit, along with nonabelian gauge fields. This leads to a mechanism which could resolve the cosmological constant problem.

scholarly journals The nature of the gravitational vacuum

2019 ◽  
Vol 28 (14) ◽  
pp. 1944005
Author(s):  
Samir D. Mathur
Keyword(s):  
Black Hole ◽  
String Theory ◽  
Cosmological Constant ◽  
Mass Formula ◽  
Vacuum Energy ◽  
Planck Scale ◽  
Cosmological Constant Problem ◽  
Horizon Radius ◽  
Number Formula ◽  
Gravitational Vacuum

The vacuum must contain virtual fluctuations of black hole microstates for each mass [Formula: see text]. We observe that the expected suppression for [Formula: see text] is counteracted by the large number [Formula: see text] of such states. From string theory, we learn that these microstates are extended objects that are resistant to compression. We argue that recognizing this ‘virtual extended compression-resistant’ component of the gravitational vacuum is crucial for understanding gravitational physics. Remarkably, such virtual excitations have no significant effect for observable systems like stars, but they resolve two important problems: (a) gravitational collapse is halted outside the horizon radius, removing the information paradox, (b) spacetime acquires a ‘stiffness’ against the curving effects of vacuum energy; this ameliorates the cosmological constant problem posed by the existence of a planck scale [Formula: see text].

scholarly journals Cosmological constant from the emergent gravity perspective

2014 ◽  
Vol 23 (06) ◽  
pp. 1430011 ◽  
Author(s):  
T. Padmanabhan ◽  
Hamsa Padmanabhan
Keyword(s):  
Cosmological Constant ◽  
Sufficient Conditions ◽  
Integration Constant ◽  
Dimensionless Number ◽  
Late Time ◽  
Field Equations ◽  
Cosmological Constant Problem ◽  
Emergent Gravity ◽  
Background Material ◽  
The Universe

Observations indicate that our universe is characterized by a late-time accelerating phase, possibly driven by a cosmological constant Λ, with the dimensionless parameter [Formula: see text], where LP= (Għ/c3)1/2is the Planck length. In this review, we describe how the emergent gravity paradigm provides a new insight and a possible solution to the cosmological constant problem. After reviewing the necessary background material, we identify the necessary and sufficient conditions for solving the cosmological constant problem. We show that these conditions are naturally satisfied in the emergent gravity paradigm in which (i) the field equations of gravity are invariant under the addition of a constant to the matter Lagrangian and (ii) the cosmological constant appears as an integration constant in the solution. The numerical value of this integration constant can be related to another dimensionless number (called CosMIn) that counts the number of modes inside a Hubble volume that cross the Hubble radius during the radiation and the matter-dominated epochs of the universe. The emergent gravity paradigm suggests that CosMIn has the numerical value 4π, which, in turn, leads to the correct, observed value of the cosmological constant. Further, the emergent gravity paradigm provides an alternative perspective on cosmology and interprets the expansion of the universe itself as a quest towards holographic equipartition. We discuss the implications of this novel and alternate description of cosmology.

scholarly journals Revisiting the Cosmological Constant Problem within Quantum Cosmology

Universe ◽  
2020 ◽  
Vol 6 (8) ◽  
pp. 108
Author(s):  
Vesselin Gueorguiev ◽  
Andre Maeder
Keyword(s):  
Energy Density ◽  
Cosmological Constant ◽  
Quantum Cosmology ◽  
Vacuum Energy ◽  
Planck Scale ◽  
Vacuum Energy Density ◽  
Characteristic Scale ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Cosmological Constant Problem

A new perspective on the Cosmological Constant Problem (CCP) is proposed and discussed within the multiverse approach of Quantum Cosmology. It is assumed that each member of the ensemble of universes has a characteristic scale a that can be used as integration variable in the partition function. An averaged characteristic scale of the ensemble is estimated by using only members that satisfy the Einstein field equations. The averaged characteristic scale is compatible with the Planck length when considering an ensemble of solutions to the Einstein field equations with an effective cosmological constant. The multiverse ensemble is split in Planck-seed universes with vacuum energy density of order one; thus, Λ˜≈8π in Planck units and a-derivable universes. For a-derivable universe with a characteristic scale of the order of the observed Universe a≈8×1060, the cosmological constant Λ=Λ˜/a2 is in the range 10−121–10−122, which is close in magnitude to the observed value 10−123. We point out that the smallness of Λ can be viewed to be natural if its value is associated with the entropy of the Universe. This approach to the CCP reconciles the Planck-scale huge vacuum energy–density predicted by QFT considerations, as valid for Planck-seed universes, with the observed small value of the cosmological constant as relevant to an a-derivable universe as observed.

scholarly journals Decrease of the effective cosmological constant in the Poincare gauge theory of gravity with a scalar field

2021 ◽  
Vol 2081 (1) ◽  
pp. 012015
Author(s):  
O V Babourova ◽  
B N Frolov
Keyword(s):  
Gauge Theory ◽  
Scalar Field ◽  
Cosmological Constant ◽  
Big Bang ◽  
Cosmological Constant Problem ◽  
Effective Cosmological Constant ◽  
Theory Of Gravity ◽  
The Big Bang ◽  
Modern Era ◽  
Gauge Theory Of Gravity

Abstract Cosmological consequences of the Poincare gauge theory of gravity are considered. An effective cosmological constant depending from the Dirac scalar field is introduced. It is proved that at the super-early Universe, the effective cosmological constant decreases exponentially from a huge value at the Big Bang to its extremely small value in the modern era, while the scale factor sharply increases and demonstrates inflationary behavior. This fact solves the well-known “cosmological constant problem” also in the Poincare gauge theory of gravity.

Solution to the Cosmological Constant Problem by Gauge Theory of Gravity

2003 ◽  
Vol 40 (2) ◽  
pp. 253-256 ◽  
Author(s):  
Wu Ning ◽  
Germano Resconi ◽  
Zheng Zhi-Peng ◽  
Xu Zhan ◽  
Zhang Da-Hua ◽  
...  
Keyword(s):  
Gauge Theory ◽  
Cosmological Constant ◽  
Cosmological Constant Problem ◽  
Theory Of Gravity ◽  
Gauge Theory Of Gravity

scholarly journals EMERGENT SPACETIME AND THE COSMOLOGICAL CONSTANT

2008 ◽  
Vol 23 (14n15) ◽  
pp. 2181-2183 ◽  
Author(s):  
HYUN SEOK YANG
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
Einstein Gravity ◽  
Cosmological Constant Problem ◽  
Emergent Gravity ◽  
Flat Spacetime ◽  
Emergent Spacetime ◽  
Dynamical Origin

We address issues on the origin of gravity and the dark energy (or the cosmological constant) from the perspectives of emergent gravity. We discuss how the emergent gravity reveals a noble, radically different picture about the origin of spacetime, which is crucial for a tenable solution of the cosmological constant problem. In particular, the emergent gravity naturally explains the dynamical origin of flat spacetime, which is absent in Einstein gravity.

Energy scale of inflation from the recurrence time of the universe

2015 ◽  
Vol 24 (03) ◽  
pp. 1550026
Author(s):  
K. Ropotenko
Keyword(s):  
Cosmological Constant ◽  
Planck Scale ◽  
Energy Scale ◽  
Recurrence Time ◽  
Inflationary Universe ◽  
De Sitter ◽  
Cosmological Constant Problem ◽  
The Universe

It is shown that the de Sitter equilibrium cosmology predicts the energy scale of inflation that significantly exceeds the Planck scale. An alternative calculation of the probability for a fluctuation into an inflationary universe is proposed which gives a more realistic energy scale of inflation. An interpretation of the cosmological constant problem in the de Sitter equilibrium cosmology is briefly discussed.

scholarly journals Bootstrapped Newtonian Cosmology and the Cosmological Constant Problem

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 358
Author(s):  
Roberto Casadio ◽  
Andrea Giusti
Keyword(s):  
Black Holes ◽  
Cosmological Constant ◽  
Quantum Cosmology ◽  
Quantum Physics ◽  
Gravitational Interaction ◽  
Newtonian Gravity ◽  
Cosmological Constant Problem ◽  
Newtonian Cosmology ◽  
Natural Solution ◽  
The Impact

Bootstrapped Newtonian gravity was developed with the purpose of estimating the impact of quantum physics in the nonlinear regime of the gravitational interaction, akin to corpuscular models of black holes and inflation. In this work, we set the ground for extending the bootstrapped Newtonian picture to cosmological spaces. We further discuss how such models of quantum cosmology can lead to a natural solution to the cosmological constant problem.

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