Quantum theory of electromagnetic fields in a cosmological quantum spacetime

Abstract

The theory of quantum fields propagating on an isotropic cosmological quantum spacetime is reexamined by generalizing the scalar test field to an electromagnetic (EM) vector field. For any given polarization of the EM field on the classical background, the Hamiltonian can be written in the form of the Hamiltonian of a set of decoupled harmonic oscillators, each corresponding to a single mode of the field. In transition from the classical to quantum spacetime background, following the technical procedure given by Ashtekar {\em et al.} [Phys. Rev. D 79, 064030 (2009)], a quantum theory of the test EM field on an effective (dressed) spacetime emerges. The nature of this emerging dressed geometry is independent of the chosen polarization, but it may depend on the energy of the corresponding field mode. Specifically, when the backreaction of the field on the quantum geometry is negligible (i.e., a test field approximation is assumed), all field modes probe the same effective background independent of the mode's energy. However, when the backreaction of the field modes on the quantum geometry is significant, by employing a Born-Oppenheimer approximation, it is shown that a rainbow (i.e., a mode-dependent) metric emerges. The emergence of this mode-dependent background in the Planck regime may have a significant effect on the creation of quantum particles. The production amount on the dressed background is computed and is compared with the familiar results on the classical geometry.

arXiv commentVersion to appear in PRD

References in corpus (23)

• Background Independent Quantum Gravity: A Status Report
• Potential Sensitivity of Gamma-Ray Burster Observations to Wave Dispersion in Vacuo
• Loop Quantum Cosmology: A Status Report
• Modern tests of Lorentz invariance
• Quantum Nature of the Big Bang
• Gravity's Rainbow
• The principle of relative locality
• A Quantum Gravity Extension of the Inflationary Scenario
• Time and a physical Hamiltonian for quantum gravity
• Loop quantum gravity effects on inflation and the CMB
• Quantum field theory on a cosmological, quantum space-time
• Falsifiable predictions from semiclassical quantum gravity
• Gravity's Rainbow: Limits for the applicability of the equivalence principle
• Stepping out of Homogeneity in Loop Quantum Cosmology
• Speedy sound and cosmic structure
• Dimensional reduction in the sky
• Quantum constraints, Dirac observables and evolution: group averaging versus Schroedinger picture in LQC
• Rainbow metric from quantum gravity
• QFT on quantum spacetime: a compatible classical framework
• Lorentz Symmetry in QFT on Quantum Bianchi I Space-Time
• Creation of particles in a cyclic universe driven by loop quantum cosmology
• Rainbow metric from quantum gravity: anisotropic cosmology
• Metric emerging to massive modes in quantum cosmological space-times

Cited by in corpus (6)

• Propagation of quantum gravity-modified gravitational waves on a classical FLRW spacetime
• Rainbow Black Hole From Quantum Gravitational Collapse
• Rainbow-like Black Hole metric from Loop Quantum Gravity
• Quantum gravity phenomenology at the dawn of the multi-messenger era -- A review
• Cosmological particle production in quantum gravity
• Regularization of the cosmological sector of loop quantum gravity with bosonic matter and the related problems with general covariance of quantum corrections