Probing gravity-related decoherence with a 16 $\mu$g Schr\"odinger cat state

TL;DR

This paper tests gravity-related modifications to quantum mechanics by observing decoherence in a 16 microgram Schrödinger cat state, aiming to understand the transition from quantum to classical behavior.

Contribution

It provides experimental evidence on gravity-induced decoherence using a macroscopic mechanical resonator in a superposition state.

Findings

No significant decoherence observed at the tested mass scale.

Constraints placed on gravity-related collapse models.

Advancement in creating and measuring large-scale quantum superpositions.

Abstract

The Schr\"odinger equation predicts the validity of the superposition principle at any scale, yet we do not experience cats being in a superposition of "dead" and "alive" in our everyday lives. Modifications to quantum theory at the fundamental level may be responsible for the objective collapse of the wave function above a critical mass, thereby breaking down the superposition principle and restoring classical behavior at the macroscopic scale. One possibility is that these modifications are related to gravity, as described by the Di\'osi-Penrose wavefunction collapse model. Here, we investigate this model using experimental measurements on the decoherence of a Schr\"odinger cat state of a mechanical resonator with an effective mass of 16 micrograms.