A Nanoscale Experiment Measuring Gravity's Role in Breaking the Unitarity of Quantum Dynamics

TL;DR

This paper proposes an experiment using nanomechanical devices to investigate whether gravity causes the breakdown of quantum unitarity, potentially revealing new physics in the quantum-classical transition.

Contribution

It introduces a specific experimental setup to test gravity's role in unitarity breaking, distinguishing it from other quantum-to-classical transition theories.

Findings

Theoretical model of gravity-induced unitarity breaking dynamics

Experimental parameters for observing the effect

Proposed protocol to identify gravity's role in quantum collapse

Abstract

Modern, state of the art nanomechanical devices are capable of creating spatial superpositions that are massive enough to begin to experimentally access the quantum to classical crossover, and thus force us to consider the possible ways in which the usual quantum dynamics may be affected. One recent theoretical proposal describes the crossover from unitary quantum mechanics to classical dynamics as a form of spontaneous symmetry breaking. Here, we propose a specific experimental setup capable of identifying the source of unitarity breaking in such a mechanism. The experiment is aimed specifically at clarifying the role played by gravity, and distinguishes the resulting dynamics from that suggested by alternative scenarios for the quantum to classical crossover. We give both a theoretical description of the expected dynamics, and a discussion of the involved experimental parameter values and the proposed experimental protocol.