Plane Gravitational Waves and Flat Space in Loop Quantum Gravity
Classically a system of arbitrary plane gravitational waves propagating in the same or opposite directions can be restricted by first-class constraints to unidirectional waves, which travel without dispersion on a flat background. The unidirectionality constraints are formulated as well-defined Loop Quantum Gravity operators, together with criteria for an anomaly-free implantation, which is crucial for the occurrence or non-occurrence of dispersion, and more generally, of local Lorentz invariance violations due to (loop) quantum effects. By a set of further first-class constraints of the same kind we construct a quantum model of a no-wave state, i.e. of empty space.
KeywordsPoisson Bracket Loop Quantum Gravity Flat Space Hamiltonian Constraint Flux Operator
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