# Cosmic quantum optical probing of quantum gravity through a gravitational lensLens

## TL;DR

This paper explores how quantum gravity effects, modeled via scalar particles around a gravitational lens, can cause decoherence and energy loss, potentially leading to observable astrophysical phenomena like anomalous redshift.

## Contribution

It introduces a model of quantum gravity effects on particles near a gravitational lens, highlighting decoherence and graviton emission as measurable phenomena.

## Key findings

- Quantum fluctuations induce decoherence of scattered particles.
- Spontaneous graviton emission reduces particle coherence and energy.
- Potential for observing anomalous redshift in astrophysical lasers.

## Abstract

We consider the nonunitary quantum dynamics of neutral massless scalar particles used to model photons around a massive gravitational lens. The gravitational interaction between the lensing mass and asymptotically free particles is described by their second-quantized scattering wavefunctions. Remarkably, the zero-point spacetime fluctuations can induce significant decoherence of the scattered states with spontaneous emission of gravitons, thereby reducing the particles' coherence as well as energy. This new effect suggests that, when photon polarizations are negligible, such quantum gravity phenomena could lead to measurable anomalous redshift of recently studied astrophysical lasers through a gravitational lens in the range of black holes and galaxy clusters.