Gravitons and light cone fluctuations. II. Correlation functions

Abstract

A model of a fluctuating lightcone due to a bath of gravitons is further investigated. The flight times of photons between a source and a detector may be either longer or shorter than the light propagation time in the background classical spacetime, and will form a Gaussian distribution centered around the classical flight time. However, a pair of photons emitted in rapid succession will tend to have correlated flight times. We derive and discuss a correlation function which describes this effect. This enables us to understand more fully the operational significance of a fluctuating lightcone. Our results may be combined with observational data on pulsar timing to place some constraints on the quantum state of cosmological gravitons.

Quantum gravitational decoherence of light and matter

“…Decoherence due to electromagnetic fluctuations as a potential new quantum vacuum effect has long attracted attention with pioneering analysis reported in [30]. Theoretically, spacetime fluctuations must also exist due to the quantization of the metric field [31,32], though details may vary with presently uncertain theories of quantum gravity. In the linearized approximation of gravity, one hopes to draw valuable analogy with QED despite differences in certain details.…”

Brownian motion in Robertson–Walker spacetimes from electromagnetic vacuum fluctuations

“…This approach can be used to treat the quantum fluctuations of the gravitational field, which has been a topic of much interest in recent years [12,13,14,15,16,17,18,19,20,21,22,23,24,25].…”

Entropic Entanglement: Information Prison Break

“…Further, several authors [27][28][29][30][31] have suggested horizon oscillations (fluctuations) are generic phenomena in quantum gravity. Let us briefly comment on the existing literature.…”