RELATIONAL TOPOLOGY AS THE FOUNDATION FOR QUANTUM GRAVITY

2005 ◽  
Vol 20 (17n18) ◽  
pp. 1261-1269 ◽  
Author(s):  
LOUIS CRANE
Keyword(s):  
General Relativity ◽  
Algebraic Geometry ◽  
Quantum Theory ◽  
Homotopy Theory ◽  
Categorical Approach ◽  
New Approach ◽  
Spin Foam Models ◽  
Spin Foam ◽  
Theory Of Gravitation ◽  
Abstract Homotopy Theory

We propose a new approach to the quantum theory of gravitation, in which the point sets of regions of spacetime are replaced by objects in a category. The objects can be constructed as limits of spin foam models, thus directly connecting to approximations to general relativity which have already been studied, and leading to a mathematically natural interpretation of the meaning of the triangulations in the spin foam models. The physical motivation for our proposal is a connection between ideas about the limited amount of information which can flow from one region to another in General Relativity, an analysis of the problem of the infinities in QFT, and the relational or categorical approach to topology in abstract homotopy theory and algebraic geometry.

scholarly journals Renormalizable and Unitary Lorentz Invariant Model of Quantum Gravity

2021 ◽  
Author(s):  
S. A. Larin
Keyword(s):  
General Relativity ◽  
Quantum Theory ◽  
Quantum Gravity ◽  
Curvature Tensor ◽  
Quantum Theory Of Gravitation ◽  
Proper Choice ◽  
Invariant Model ◽  
Self Consistent ◽  
Theory Of Gravitation

We analyze the R + R2 model of quantum gravity where terms quadratic in the curvature tensor are added to the General Relativity action. This model was recently proved to be a self-consistent quantum theory of gravitation, being both renormalizable and unitary. The model can be made practically indistinguishable from General Relativity at astrophysical and cosmological scales by the proper choice of parameters.

scholarly journals GRAVITY AS BF THEORY PLUS POTENTIAL

2009 ◽  
Vol 24 (15) ◽  
pp. 2776-2782 ◽  
Author(s):  
KIRILL KRASNOV
Keyword(s):  
General Relativity ◽  
Models Of Quantum Gravity ◽  
Quantum Gravity ◽  
Alternative Formulation ◽  
Potential Term ◽  
Bf Theory ◽  
Spin Foam Models ◽  
Spin Foam ◽  
To Come

Spin foam models of quantum gravity are based on Plebanski's formulation of general relativity as a constrained BF theory. We give an alternative formulation of gravity as BF theory plus a certain potential term for the B-field. When the potential is taken to be infinitely steep one recovers general relativity. For a generic potential the theory still describes gravity in that it propagates just two graviton polarizations. The arising class of theories is of the type amenable to spin foam quantization methods, and, we argue, may allow one to come to terms with renormalization in the spin foam context.

scholarly journals Universality of the Einstein theory of gravitation

2016 ◽  
Vol 13 (08) ◽  
pp. 1640008 ◽  
Author(s):  
Jerzy Kijowski
Keyword(s):  
General Relativity ◽  
Variational Problems ◽  
Relativity Theory ◽  
General Relativity Theory ◽  
Einstein Theory ◽  
Metric Tensor ◽  
New Approach ◽  
Theory Of Gravitation ◽  
Tensor Formula ◽  
Matter Fields

We show that generalizations of general relativity theory, which consist in replacing the Hilbert Lagrangian [Formula: see text] by a generic scalar density [Formula: see text] depending upon the metric [Formula: see text] and the curvature tensor [Formula: see text], are equivalent to the conventional Einstein theory for a (possibly) different metric tensor [Formula: see text] and (possibly) a different set of matter fields. The simple proof of this theorem relies on a new approach to variational problems containing metric and connection.

scholarly journals Renormalizable and Unitary Lorentz Invariant Model of Quantum Gravity

Universe ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 435
Author(s):  
Sergey A. Larin
Keyword(s):  
General Relativity ◽  
Quantum Theory ◽  
Quantum Gravity ◽  
Curvature Tensor ◽  
Quantum Theory Of Gravitation ◽  
Proper Choice ◽  
Invariant Model ◽  
Self Consistent ◽  
Theory Of Gravitation

We analyze the R+R2 model of quantum gravity where terms quadratic in the curvature tensor are added to the General Relativity action. This model was recently proved to be a self-consistent quantum theory of gravitation, being both renormalizable and unitary. The model can be made practically indistinguishable from General Relativity at astrophysical and cosmological scales by the proper choice of parameters.

scholarly journals NEW SPIN FOAM MODELS OF QUANTUM GRAVITY

2005 ◽  
Vol 20 (17n18) ◽  
pp. 1305-1313
Author(s):  
A. MIKOVIĆ
Keyword(s):  
General Relativity ◽  
Models Of Quantum Gravity ◽  
Quantum Gravity ◽  
Path Integral ◽  
Critical Review ◽  
Loop Quantum Gravity ◽  
Spin Networks ◽  
Spin Foam Models ◽  
Spin Foam Model ◽  
Spin Foam

We give a brief and a critical review of the Barret-Crane spin foam models of quantum gravity. Then we describe two new spin foam models which are obtained by direct quantization of General Relativity and do not have some of the drawbacks of the Barret-Crane models. These are the model of spin foam invariants for the embedded spin networks in loop quantum gravity and the spin foam model based on the integration of the tetrads in the path integral for the Palatini action.

scholarly journals Structuralism, Invariance, and Univalence

2018 ◽  
Author(s):  
Steve Awodey
Keyword(s):  
Type Theory ◽  
Homotopy Theory ◽  
Mathematical Practice ◽  
New Approach ◽  
Constructive Type Theory ◽  
Homotopy Type Theory ◽  
Computational Implementation ◽  
Geometric Content ◽  
Abstract Homotopy Theory ◽  
New System

The recent discovery of an interpretation of constructive type theory into abstract homotopy theory suggests a new approach to the foundations of mathematics with intrinsic geometric content and a computational implementation. Voevodsky has proposed such a program, including a new axiom with both geometric and logical significance: the univalence axiom. It captures the familiar aspect of informal mathematical practice according to which one can identify isomorphic objects. This powerful addition to homotopy type theory gives the new system of foundations a distinctly structural character.

scholarly journals Entropic Description of Gravity by Thermodynamics Relativistic Fluids and the Information Theory

2019 ◽  
Author(s):  
Roman Baudrimont
Keyword(s):  
Information Theory ◽  
General Relativity ◽  
Quantum Theory ◽  
Fluid Mechanics ◽  
Quantum Physics ◽  
Relativistic Fluids ◽  
New Approach ◽  
Von Neumann ◽  
Entropic Gravity ◽  
Theory Of Information

The purpose of this paper is to show a new approach to unify the theory of general relativity and quantum physics. For this, we rely on thermodynamics, fluid mechanics and the theory of information. We will then see that the Shannon entropy, Boltzmann and Von Neumann can be the source of gravity, which would be a form emerging. For this, we will study at first what is lacking for the unification of general relativity and physics. Secondly, we will explain the concept of entropic gravity by introducing calculations Erik Verlinde. Then we will explain the concept of entropy Boltzmann, Shannon, Von Neumann and the links between them. Then, we will modify Einstein's equations by transforming the tensor of perfect fluid in terms of entropy. Finally, we will link our theory with experience already carried out as part of a link between gravity and quantum theory.

scholarly journals MEASUREMENTS AND INFORMATION IN SPIN FOAM MODELS

2012 ◽  
Vol 27 (28) ◽  
pp. 1250164
Author(s):  
J. MANUEL GARCÍA-ISLAS
Keyword(s):  
Information Theory ◽  
Quantum Gravity ◽  
Cosmological Constant ◽  
Shannon Entropy ◽  
Three Dimensional ◽  
Spin Network ◽  
Spin Foam Models ◽  
Foam Model ◽  
Spin Foam Model ◽  
Spin Foam

In the three-dimensional spin foam model of quantum gravity with a cosmological constant, there exists a set of observables associated with spin network graphs. A set of probabilities is calculated from these observables, and hence the associated Shannon entropy can be defined. We present the Shannon entropy associated with these observables and find some interesting bounded inequalities. The problem relates measurements, entropy and information theory in a simple way which we explain.

scholarly journals Relativity and the quantum theory

1928 ◽  
Vol 117 (778) ◽  
pp. 630-637 ◽  
Keyword(s):  
Quantum Theory ◽  
Space Time ◽  
Theory Of Gravitation ◽  
The Law

In Einstein’s theory of gravitation it is assumed that the geometry of space- time is characterised by the following equation for the measurement of displacement:— ds 2 = g mn dx m dx n { m n = 1, 2, 3, 4, the sign of summation being omitted for convenience. It is supposed that the coefficients, of which g mn is the type, are dependent upon the content of space, and the relation existing between them is the law of gravitation.

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