Group-theoretical structure of quantum measurements and equivalence principle

TL;DR

This paper explores how quantum measurements in gravitational fields can reveal information about gravity, potentially challenging the equivalence principle at the quantum level and linking it to the quantum nature of gravity.

Contribution

It analyzes the group-theoretical structure of quantum measurements in gravitational fields and discusses how these measurements may lead to a breakdown of the equivalence principle at quantum scales.

Findings

Quantum measurements can contain information about gravitational fields.

The equivalence principle may break down in quantum measurement scenarios.

Quantum properties of gravity might prevent violation of the equivalence principle.

Abstract

The transverse group associated to some continuous quantum measuring processes is analyzed in the presence of nonvanishing gravitational fields. This is done considering, as an exmaple, the case of a particle whose coordinates are being monitored. Employing the so called restricted path integral formalism, it will be shown that the measuring process could always contain information concerning the gravitational field. In other words, it seems that with the presence of a measuring process the equivalence principle may, in some cases, break down. The relation between the breakdown of the equivalence principle, at quantum level, and the fact that the gravitational field could act always as a decoherence environment, is also considered. The phenomena of quantum beats of quantum optics will allow us to consider the possibility that the experimental corroboration of the equivalence principle at quantum level could be taken as an indirect evidence in favor of the quantization of the gravitational field, i.e., the quantum properties of this field avoid the violation of the equivalence principle.