scholarly journals From quantum gravity to quantum field theory via noncommutative geometry

2014 ◽  
Vol 31 (3) ◽  
pp. 035018 ◽  
Author(s):  
Johannes Aastrup ◽  
Jesper Møller Grimstrup
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Quantum Gravity ◽  
Noncommutative Geometry ◽  
Quantum Field

The Higgs impact on Einstein’s gravity: The Einstein–Kraichnan quantum gravity

2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040012
Author(s):  
M. D. Maia ◽  
V. B. Bezerra
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Standard Model ◽  
Quantum Gravity ◽  
Higgs Mechanism ◽  
Quantum Field ◽  
Einstein’S Equations ◽  
Einstein's Equations ◽  
Fundamental Interactions ◽  
The Standard Model

An updated review of Kraichnan’s derivation of Einstein’s equations from quantum field theory is presented, including the period after the discovery of the Higgs mechanism and the inclusion of gravitation within the Standard Model of Fundamental Interactions.

scholarly journals Finite quantum field theory in noncommutative geometry

1996 ◽  
Vol 35 (2) ◽  
pp. 231-244 ◽  
Author(s):  
H. Grosse ◽  
C. Klimčík ◽  
P. Prešnajder
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Noncommutative Geometry ◽  
Quantum Field

scholarly journals Macroscopic traversable wormholes with zero tidal forces inspired by noncommutative geometry

2015 ◽  
Vol 24 (03) ◽  
pp. 1550023 ◽  
Author(s):  
Peter K. F. Kuhfittig
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Energy Density ◽  
Noncommutative Geometry ◽  
Energy Condition ◽  
Null Energy Condition ◽  
Quantum Field ◽  
Tidal Forces ◽  
Traversable Wormholes ◽  
Asymptotic Flatness

This paper addresses the following issues: (1) the possible existence of macroscopic traversable wormholes, given a noncommutative-geometry background and (2) the possibility of allowing zero tidal forces, given a known density. It is shown that whenever the energy density describes a classical wormhole, the resulting solution is incompatible with quantum-field theory. If the energy density originates from noncommutative geometry, then zero tidal forces are allowed. Also attributable to the noncommutative geometry is the violation of the null energy condition. The wormhole geometry satisfies the usual requirements, including asymptotic flatness.

scholarly journals The Hilbert space of quantum gravity is locally finite-dimensional

2017 ◽  
Vol 26 (12) ◽  
pp. 1743013 ◽  
Author(s):  
Ning Bao ◽  
Sean M. Carroll ◽  
Ashmeet Singh
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Hilbert Space ◽  
Quantum Gravity ◽  
Density Operator ◽  
Small Region ◽  
Quantum Field ◽  
Locally Finite ◽  
Finite Dimensional ◽  
Model Independent

We argue in a model-independent way that the Hilbert space of quantum gravity is locally finite-dimensional. In other words, the density operator describing the state corresponding to a small region of space, when such a notion makes sense, is defined on a finite-dimensional factor of a larger Hilbert space. Because quantum gravity potentially describes superpositions of different geometries, it is crucial that we associate Hilbert-space factors with spatial regions only on individual decohered branches of the universal wave function. We discuss some implications of this claim, including the fact that quantum-field theory cannot be a fundamental description of nature.

scholarly journals The correspondence principle in quantum field theory and quantum gravity

2018 ◽  
Author(s):  
Damiano Anselmi
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Quantum Mechanics ◽  
Quantum Gravity ◽  
Correspondence Principle ◽  
External World ◽  
Quantum Field ◽  
Human Ability ◽  
Local Symmetries ◽  
Matter Sector

We discuss the fate of the correspondence principle beyond quantum mechanics, specifically in quantum field theory and quantum gravity, in connection with the intrinsic limitations of the human ability to observe the external world. We conclude that the best correspondence principle is made of unitarity, locality, proper renormalizability (a refinement of strict renormalizability), combined with fundamental local symmetries and the requirement of having a finite number of fields. Quantum gravity is identified in an essentially unique way. The gauge interactions are uniquely identified in form. Instead, the matter sector remains basically unrestricted. The major prediction is the violation of causality at small distances.

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