Chiral vacuum fluctuations in quantum gravity

Abstract

We examine tensor perturbations around a deSitter background within the framework of Ashtekar's variables and cousins parameterized by the Immirzi parameter $\gamma$. At the classical level we recover standard cosmological perturbation theory, with illuminating insights. Quantization leads to real novelties. In the low energy limit we find a second quantized theory of gravitons which displays different vacuum fluctuations for right and left gravitons. Nonetheless right and left gravitons have the same (positive) energies, resolving a number of paradoxes suggested in the literature. The right-left asymmetry of the vacuum fluctuations depends on $\gamma$ and the ordering of the Hamiltonian constraint, and it would leave a distinctive imprint in the polarization of the cosmic microwave background, thus opening quantum gravity to observational test.

References in corpus (9)

• Graviton propagator from background-independent quantum gravity
• LQG propagator from the new spin foams
• Anomalous CMB polarization and gravitational chirality
• Gravitons and Loops
• An algebraic extension of Dirac quantization: Examples
• A Note On The Chern-Simons And Kodama Wavefunctions
• The linearization of the Kodama state
• Superconducting loop quantum gravity and the cosmological constant
• Quantum gravity as a Fermi liquid

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• Detecting chiral gravity with the pure pseudospectrum reconstruction of the cosmic microwave background polarized anisotropies
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• Modifications in the Spectrum of Primordial Gravitational Waves Induced by Instantonic Fluctuations
• Linking shape dynamics and loop quantum gravity
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