Quantum Measurement, Gravitation, and Locality

TL;DR

This paper explores how high-energy quantum measurements near the Planck scale can fundamentally alter spacetime, challenging the assumption of locality due to gravitational effects on measurement processes.

Contribution

It demonstrates that at Planck-scale energies, measurement-induced spacetime changes invalidate the usual notion of locality in quantum mechanics.

Findings

Measurement processes at Planck energies alter spacetime geometry.

Altered spacetime destroys the commutativity of position operators.

Locality assumption breaks down at fundamental energy scales.

Abstract

This essay argues that when measurement processes involve energies of the order of the Planck scale, the fundamental assumption of locality may no longer be a good approximation. Idealized position measurements of two distinguishable spin-$0$ particles are considered. The measurements alter the space-time metric in a fundamental manner governed by the commutation relations $[x_i\,\,p_j]= i\hbar\,\delta_{ij}$ and the classical field equations of gravitation. This {\it in-principle} unavoidable change in the space-time metric destroys the commutativity (and hence locality) of position measurement operators.