Does Quantum Mechanics Clash with the Equivalence Principle - and Does it Matter?

TL;DR

This paper examines whether quantum mechanics conflicts with the equivalence principle of general relativity, concluding that such conflicts are unlikely to be found or are already evident, and discusses implications for understanding geometric theories.

Contribution

It clarifies the ambiguous nature of the equivalence principle and argues that quantum tests are unlikely to reveal fundamental clashes, offering philosophical insights into geometric theories.

Findings

Quantum tests of the equivalence principle are unlikely to show conflicts.

The clash or non-clash is either already evident or guaranteed not to exist.

The work provides philosophical insights into the nature of geometric theories.

Abstract

With an eye on developing a quantum theory of gravity, many physicists have recently searched for quantum challenges to the equivalence principle of general relativity. However, as historians and philosophers of science are well aware, the principle of equivalence is not so clear. When clarified, we think quantum tests of the equivalence principle won't yield much. The problem is that the clash/not-clash is either already evident or guaranteed not to exist. Nonetheless, this work does help teach us what it means for a theory to be geometric.