scholarly journals Chiral Vacuum Fluctuations in Quantum Gravity

2011 ◽  
Vol 106 (12) ◽  
Author(s):  
João Magueijo ◽  
Dionigi M. T. Benincasa
Keyword(s):  
Quantum Gravity ◽  
Vacuum Fluctuations

SOME FUNDAMENTAL ASPECTS OF SEMICLASSICAL AND QUANTUM GRAVITY

1989 ◽  
Vol 04 (18) ◽  
pp. 4735-4818 ◽  
Author(s):  
T. PADMANABHAN
Keyword(s):  
Quantum Gravity ◽  
Semiclassical Limit ◽  
Vacuum Fluctuations ◽  
Constraint Equations ◽  
Semiclassical Gravity ◽  
Recent Developments ◽  
Definition Of

Some recent developments in the study of quantum gravity and its semiclassical limit are reviewed. The discussion includes the role of constraint equations in quantization, the definition of 'time' in the semiclassical limit, the various forms of 'backreaction' in semiclassical gravity and the role of vacuum fluctuations in quantum gravity.

scholarly journals Metrics with Zero and Almost-Zero Einstein Action in Quantum Gravity

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1288 ◽  
Author(s):  
Giovanni Modanese
Keyword(s):  
Gravitational Field ◽  
Quantum Gravity ◽  
Scalar Curvature ◽  
Spontaneous Polarization ◽  
Spherical Symmetry ◽  
Metropolis Algorithm ◽  
Vacuum Fluctuations ◽  
Spacetime Foam

We generate numerically on a lattice an ensemble of stationary metrics, with spherical symmetry, which have Einstein action SE « ћ. This is obtained through a Metropolis algorithm with weight exp(−β2S2E) and β » ћ−1. The squared action in the exponential allows to circumvene the problem of the non-positivity of SE. The discretized metrics obtained exhibit a spontaneous polarization in regions of positive and negative scalar curvature. We compare this ensemble with a class of continuous metrics previously found, which satisfy the condition SE = 0 exactly, or in certain cases even the stronger condition R(x) = 0 for any x. All these gravitational field configurations are of considerable interest in quantum gravity, because they represent possible vacuum fluctuations and are markedly different from Wheeler’s “spacetime foam”.

scholarly journals Metrics with Zero and Almost-zero Einstein Action in Quantum Gravity

2019 ◽  
Author(s):  
Giovanni Modanese
Keyword(s):  
Gravitational Field ◽  
Quantum Gravity ◽  
Scalar Curvature ◽  
Spontaneous Polarization ◽  
Spherical Symmetry ◽  
Metropolis Algorithm ◽  
Vacuum Fluctuations ◽  
Spacetime Foam

We generate numerically on a lattice an ensemble of stationary metrics, with spherical symmetry, which have Einstein action SE « ħ. This is obtained through a Metropolis algorithm with weight exp(-β2SE2) and β » ħ-1. The squared action in the exponential allows to circumvene the problem of the non-positivity of SE. The discretized metrics obtained exhibit a spontaneous polarization in regions of positive and negative scalar curvature. We compare this ensemble with a class of continuous metrics previously found, which satisfy the condition SE=0 exactly, or in certain cases even the stronger condition R(x)=0 for any x. All these gravitational field configurations are of considerable interest in quantum gravity, because they represent possible vacuum fluctuations and are markedly different from Wheeler's ''spacetime foam''.

scholarly journals Chiral vacuum fluctuations in quantum gravity

2012 ◽  
Vol 360 ◽  
pp. 012003
Author(s):  
Laura Bethke ◽  
João Magueijo
Keyword(s):  
Quantum Gravity ◽  
Vacuum Fluctuations

scholarly journals The vecro hypothesis

2020 ◽  
Vol 29 (15) ◽  
pp. 2030009
Author(s):  
Samir D. Mathur
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Gravity ◽  
Black Hole Horizon ◽  
Cosmological Horizon ◽  
Leading Order ◽  
Vacuum Fluctuations ◽  
Curved Spacetime ◽  
Black Hole Information

We consider three fundamental issues in quantum gravity: (a) the black hole information paradox (b) the unboundedness of entropy that can be stored inside a black hole horizon (c) the relation between the black hole horizon and the cosmological horizon. With help from the small corrections theorem, we convert each of these issues into a sharp conflict. We then argue that all three conflicts can be resolved by the following hypothesis: the vacuum wave functional of quantum gravity contains a “vecro” component made of virtual fluctuations of configurations of the same type that arise in the fuzzball structure of black hole microstates. Further, if we assume that causality holds to leading order in gently curved spacetime, then we must have such a vecro component in order to resolve the above conflicts. The term vecro stands for “Virtual Extended Compression-Resistant Object”, and characterizes the nature of the vacuum fluctuations that resolve the puzzles. It is interesting that puzzle (c) may relate the role of quantum gravity in black holes to observations in the sky.

scholarly journals QUANTUM NATURE OF BLACK HOLES

2004 ◽  
Vol 13 (10) ◽  
pp. 2299-2305 ◽  
Author(s):  
ADAM D. HELFER
Keyword(s):  
Black Holes ◽  
Quantum Gravity ◽  
Gravitational Collapse ◽  
Dominant Role ◽  
High Energy ◽  
Ultra High Energy ◽  
Quantum Fields ◽  
Vacuum Fluctuations ◽  
High Energies ◽  
Quantum Nature

I reconsider Hawking's analysis of the effects of gravitational collapse on quantum fields, taking into account interactions between the fields. The ultra-high energy vacuum fluctuations, which had been considered to be an awkward peripheral feature of the analysis, are shown to play a key role. By interactions, they can scatter particles to, or create pairs of particle at, ultra-high energies. The energies rapidly become so great that quantum gravity must play a dominant role. Thus the vicinities of black holes are essentially quantum-gravitational regimes.

Topology knots and hierarchy problem

2019 ◽  
Author(s):  
Vitaly Kuyukov
Keyword(s):  
Quantum Theory ◽  
String Theory ◽  
Quantum Gravity ◽  
Dimensional Space ◽  
Space Time ◽  
Elementary Particles ◽  
Hierarchy Problem ◽  
Topological Quantum ◽  
Dimensional Space Time ◽  
New Formula

Many approaches to quantum gravity consider the revision of the space-time geometry and the structure of elementary particles. One of the main candidates is string theory. It is possible that this theory will be able to describe the problem of hierarchy, provided that there is an appropriate Calabi-Yau geometry. In this paper we will proceed from the traditional view on the structure of elementary particles in the usual four-dimensional space-time. The only condition is that quarks and leptons should have a common emerging structure. When a new formula for the mass of the hierarchy is obtained, this structure arises from topological quantum theory and a suitable choice of dimensional units.

Braking effect in quantum gravity

2020 ◽  
Author(s):  
Vitaly Kuyukov
Keyword(s):  
Quantum Gravity

Braking effect in quantum gravity

Sign in / Sign up

Export Citation Format

Share Document