Is a tabletop search for Planck scale signals feasible?

TL;DR

This paper proposes a feasible tabletop experiment using current ultrahigh vacuum and cryogenic technology to detect Planck scale signals, potentially testing quantum gravity effects like spacetime foam.

Contribution

It introduces a novel experimental scheme combining photon and macroscopic probe to test quantum foam without requiring Planck-length localization.

Findings

Potential sensitivity to Planck scale signals with current technology

Experimental scheme is based on energy and momentum conservation

Does not depend on specific quantum gravity models

Abstract

Quantum gravity theory is untested experimentally. Could it be tested with tabletop experiments? While the common feeling is pessimistic, a detailed inquiry shows it possible to sidestep the onerous requirement of localization of a probe on Planck length scale. I suggest a tabletop experiment which, given state of the art ultrahigh vacuum and cryogenic technology, could already be sensitive enough to detect Planck scale signals. The experiment combines a single photon's degree of freedom with one of a macroscopic probe to test Wheeler's conception of "quantum foam", the assertion that on length scales of the order Planck's, spacetime is no longer a smooth manifold. The scheme makes few assumptions beyond energy and momentum conservations, and is not based on a specific quantum gravity scheme.