On the detectability of quantum spacetime foam with gravitational-wave interferometers

TL;DR

This paper critically examines the proposal that quantum spacetime foam effects could be detectable with gravitational-wave interferometers, arguing that the foundational uncertainty limits are based on unrealistic assumptions, thus challenging the detectability claim.

Contribution

The paper refutes the claim that quantum foam effects are detectable at large scales by analyzing and invalidating the underlying uncertainty limits used in the proposal.

Findings

Wigner's uncertainty limit relies on unrealistic assumptions.

Removing assumptions invalidates the proposed detectability.

Quantum foam effects are unlikely to be detectable with current interferometers.

Abstract

We discuss a recent provocative suggestion by Amelino-Camelia and others that classical spacetime may break down into ``quantum foam'' on distance scales many orders of magnitude larger than the Planck length, leading to effects which could be detected using large gravitational wave interferometers. This suggestion is based on a quantum uncertainty limit obtained by Wigner using a quantum clock in a gedanken timing experiment. Wigner's limit, however, is based on two unrealistic and unneccessary assumptions: that the clock is free to move, and that it does not interact with the environment. Removing either of these assumptions makes the uncertainty limit invalid, and removes the basis for Amelino-Camelia's suggestion.