Testing spontaneous collapse through bulk heating experiments: estimate of the background noise

TL;DR

This paper evaluates the background noise from cosmic rays and gamma radiation in underground experiments to determine the feasibility of detecting spontaneous wave function collapse-induced heating.

Contribution

It provides an estimate of background noise levels at various depths, showing that deep underground experiments can detect collapse-induced heating with current technology.

Findings

Background noise decreases with depth, enabling clearer detection.

A depth of 6.5 km.w.e. reduces noise sufficiently for collapse rate detection.

Current technology is capable of detecting the predicted heating rate.

Abstract

Models of spontaneous wave function collapse predict a small heating rate for a bulk solid, as a result of coupling to the noise field that causes collapse. This rate is small enough that ambient radioactivity and cosmic ray flux on the surface of the earth can mask the heating due to spontaneous collapse. In this paper we estimate the background noise due to gamma-radiation and cosmic ray muon flux, at different depths. We demonstrate that a low-temperature underground experiment at a depth of about 6.5 km.w.e. would have a low enough background to allow detection of bulk heating for a collapse rate $\lambda$ of $10^{-16}$ s$^{-1}$ using presently available technology.