The ongoing quest for quantum gravity - a framework that can consistently explain physics of matter and gravity at all length scales - faces profound challenges. From the theory side, perturbative quantization approaches which succeeded for other fundamental forces leads to non-renormalizable divergences for gravity. On the other hand, observational signatures are foreseen at energy scales (Planck scale ~10¹⁹ GeV) that far surpass the current limits set by the Large Hadron Collider (~10⁴ GeV). In this context, the semi-classical approach serves as an accessible middle-ground for probing non-trivial phenomena that can otherwise only be rigorously explained by quantum gravity. The central premise here is the quantization of fluctuations in a classical, mean-field background geometry.

Quantum information theory provides a powerful toolbox for analyzing semi-classical predictions such as (i) the evaporation of black holes through Hawking radiation, and (ii) the generation of primordial density perturbations from vacuum fluctuations in the early-universe. Recent advances in cold atom physics have further facilitated the successful simulation of these phenomena via analogue gravity experiments, opening up highly interdisciplinary avenues for testing semi-classical predictions.