Quantum Detection of Conicity

TL;DR

This paper demonstrates that an Unruh-DeWitt detector can detect global geometric features like a deficit angle in spacetime, even when placed in flat regions away from the actual structure.

Contribution

It shows that quantum detectors can sense global spacetime features such as deficit angles without direct interaction with the structure causing them.

Findings

Detector response varies with the deficit angle

Sensitivity occurs despite the detector being outside the structure

Global spacetime features influence local quantum measurements

Abstract

We investigate the sensitivity of an Unruh-DeWitt detector to the global features of a deficit angle that are otherwise classically inaccessible. Specifically, we consider a detector placed inside an infinite thin hollow cylinder whose spacetime is everywhere flat but outside of which the spacetime has a deficit angle and study its response to a scalar field to which it couples. We find that the response of the detector is sensitive to the deficit angle, despite the fact that it does not interact with the cylinder.