Decoherence from the light bending interaction

TL;DR

This paper investigates a gravitationally induced decoherence effect caused by light bending interactions, revealing how unobserved light can cause quantum coherence loss in massive bodies, with implications for quantum gravity and optomechanics.

Contribution

It introduces a quantum model of light bending interaction leading to decoherence, providing explicit lengthscale calculations for various light states and highlighting its fundamental significance.

Findings

Decoherence lengthscales are derived for thermal and coherent light.

The effect is extremely weak for typical light energies.

Fundamental implications for quantum gravity and optomechanics are discussed.

Abstract

We analyse a decoherence effect, caused by the gravitational interaction between a massive body and the electromagnetic field. Assuming a quantum version of the light bending interaction, we show that it leads to decoherence of the mass if the light is not observed. Using the extreme weakness of the gravitational coupling, we derive explicitly the decoherence lengthscales for general states of the central mass and for both thermal and coherent light. Predictably, the effect is very faint for anything but hugely energetic light, however from the fundamental point of view of co-existence of both gravitation and quantum theories, it is there. Since effectively the studied system is a quantum optomechanical system, we hope our results, properly rescaled, will be also useful in optomechanics.