Inflationary observables in loop quantum cosmology

Abstract

The full set of cosmological observables coming from linear scalar and tensor perturbations of loop quantum cosmology is computed in the presence of inverse-volume corrections. Background inflationary solutions are found at linear order in the quantum corrections; depending on the values of quantization parameters, they obey an exact or perturbed power-law expansion in conformal time. The comoving curvature perturbation is shown to be conserved at large scales, just as in the classical case. Its associated Mukhanov equation is obtained and solved. Combined with the results for tensor modes, this yields the scalar and tensor indices, their running, and the tensor-to-scalar ratio, which are all first order in the quantum correction. The latter could be sizable in phenomenological scenarios. Contrary to a pure minisuperspace parametrization, the lattice refinement parametrization is in agreement with both anomaly cancellation and our results on background solutions and linear perturbations. The issue of the choice of parametrization is also discussed in relation with a possible superluminal propagation of perturbative modes, and conclusions for quantum spacetime structure are drawn.

41 pages; v2: minor typos corrected, summary of results added

References in corpus (18)

• Quantum Nature of the Big Bang: Improved dynamics
• Anomaly freedom in perturbative loop quantum gravity
• Loop quantum gravity corrections to gravitational wave dispersion
• Loop quantum cosmology and inhomogeneities
• Large scale effective theory for cosmological bounces
• Lattice refining loop quantum cosmology, anisotropic models and stability
• Cosmological footprints of loop quantum gravity
• Consistent Loop Quantum Cosmology
• Super-inflation in Loop Quantum Cosmology
• Formation and Evolution of Structure in Loop Cosmology
• Hamiltonian cosmological perturbation theory with loop quantum gravity corrections
• Effective Constraints for Quantum Systems
• Cosmological vector modes and quantum gravity effects
• The gravitational wave background from super-inflation in Loop Quantum Cosmology
• Effective constraints of loop quantum gravity
• Harmonic cosmology: How much can we know about a universe before the big bang?
• Inflationary scalar spectrum in loop quantum cosmology
• Constraints on a scale invariant power spectrum from superinflation in LQC