On the testability of the K\'arolyh\'azy model

TL;DR

This paper reevaluates Károlyházy's model of space-time fluctuations causing decoherence, addressing previous issues by considering more general correlation functions, thus restoring its viability.

Contribution

It introduces a broader class of correlation functions for space-time fluctuations, resolving previous radiation emission problems and reviving the model's testability.

Findings

Resolved the radiation emission issue in Károlyházy's model

Demonstrated the viability of the model with generalized correlation functions

Revived the potential for experimental tests of space-time fluctuations

Abstract

K\'arolyh\'azy's original proposal, suggesting that space-time fluctuations could be a source of decoherence in space, faced a significant challenge due to an unexpectedly high emission of radiation (13 orders of magnitude more than what was observed in the latest experiment). To address this issue, we reevaluated K\'arolyh\'azy's assumption that the stochastic metric fluctuation must adhere to a wave equation. By considering more general correlation functions of space-time fluctuations, we resolve the problem and consequently revive the aforementioned proposal.