Results 1 
2 of
2
On the Ground State of Quantum Gravity
, 1997
"... In order to gain insight into the possible Ground State of Quantized Einstein’s Gravity, we have devised a variational calculation of the energy of the quantum gravitational field in an open space, as measured by an asymptotic observer living in an asymptotically flat spacetime. We find that for Qu ..."
Abstract

Cited by 1 (1 self)
 Add to MetaCart
(Show Context)
In order to gain insight into the possible Ground State of Quantized Einstein’s Gravity, we have devised a variational calculation of the energy of the quantum gravitational field in an open space, as measured by an asymptotic observer living in an asymptotically flat spacetime. We find that for Quantum Gravity (QG) it is energetically favourable to perform its quantum fluctuations not upon flat spacetime but around a “gas ” of wormholes, whose size is the Planck length ap (ap ≃ 10 −33 cm). As a result, assuming such configuration to be a good approximation to the true Ground State of Quantum Gravity, spacetime, the arena of physical reality, turns out to be well described by Wheeler’s Quantum Foam and adequately modeled by a spacetime lattice with lattice constant ap, the Planck lattice.
The Friedmann Equations
"... Contents 1 Introduction 1 2 Cosmological field equations 2 2.1 Definition of curvature tensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.2 Christoffel symbols for the FRWmetric . . . . . . . . . . . . . . . . . . . . . . . 3 2.3 Components of the Ricci tensor . . . . . . . . . . ..."
Abstract
 Add to MetaCart
Contents 1 Introduction 1 2 Cosmological field equations 2 2.1 Definition of curvature tensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.2 Christoffel symbols for the FRWmetric . . . . . . . . . . . . . . . . . . . . . . . 3 2.3 Components of the Ricci tensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.4 Einstein tensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.5 Energymomentum tensor for a perfect fluid . . . . . . . . . . . . . . . . . . . . . 9 2.6 The Friedmann Equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3 Cosmological models 11 3.1 Expansion regimes: equation of state . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.2 Cosmological parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.3 Curvature and critical density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.4 Radial motion of a particle in a