Semiclassical Length Measure from a Quantum-Gravity Wave Function

Abstract

The definition of a length operator in quantum cosmology is usually influenced by a~quantum theory for gravity considered. The semiclassical limit at the Planck age must meet the requirements implied in present observations. The features of a semiclassical wave-functional state are investigated, for which the modern measure(ment)s is consistent. The results of a length measurement at present times are compared with the same measurement operation at cosmological times. By this measure, it is possible to discriminate, within the same Planck-length expansion, the corrections to a Minkowski flat space possibly due to classicalization of quantum phenomena at the Planck time and those due to possible quantum-gravitational manifestations of present times. This~analysis and the comparison with the previous literature can be framed as a test for the verification of the time at which anomalies at present related to the gravitational field, and, in particular, whether they are ascribed to the classicalization epoch. Indeed, it allows to discriminate not only within the possible quantum features of the quasi (Minkowski) flat spacetime, but also from (possibly Lorentz violating) phenomena detectable at high-energy astrophysical scales. The results of two different (coordinate) length measures have been compared both at cosmological time and as a perturbation element on flat Minkowski spacetime. The differences for the components of the corresponding classical(ized) metric tensor have been analyzed at different orders of expansions. The comparison of the results of (straight) length measures in two different directions, in particular, can encode the pertinent information about the parameters defining the semiclassical wavefunctional for (semiclassicalized) gravitational field.

27 pages; accepted for publication on Technologies, Special Issue "Quantum Gravity Phenomenology and Experimental Implications"

References in corpus (27)

• Quantum Nature of the Big Bang: An Analytical and Numerical Investigation
• Polyhedra in loop quantum gravity
• The causal set approach to quantum gravity
• The length operator in Loop Quantum Gravity
• Bianchi Model CMB Polarization and its Implications for CMB Anomalies
• Quantum geometrodynamics: whence, whither?
• New length operator for loop quantum gravity
• Towards the graviton from spinfoams: higher order corrections in the 3d toy model
• Dynamics of a magnetized Bianchi I universe with vacuum energy
• Comparing Planck and WMAP: Maps, Spectra, and Parameters
• Loop Quantum Gravity Phenomenology: Linking Loops to Observational Physics
• Have we tested Lorentz invariance enough?
• On the Causal Set-Continuum Correspondence
• The Effective Planck Mass and the Scale of Inflation
• Experimental search for a Lorentz invariant spacetime granularity: Possibilities and bounds
• Implication of geodesic equation in Generalized Uncertainty Principle framework
• Polarized Spots in Anisotropic Open Universes
• Quantum Gravitational Uncertainty of Transverse Position
• Spacetime Indeterminacy and Holographic Noise
• A forecast for the detection of the power asymmetry from galaxy surveys
• Quantum Indeterminacy of Emergent Spacetime
• Semiclassical Horizons
• Classical and Quantum Polyhedra
• About the Minimal Resolution of Space-Time Grains in Experimental Quantum Gravity
• Separating CMB Stokes Q and U polarization signals from Non-Gaussian Emissions
• Special Relativity in Quantum Phase Space
• Test of cosmic isotropy in the Planck era