Comparing Superpositions of Classical and Quantum-CoM Detectors

Abstract

Particle detector models are powerful tools for probing different quantum fields or spacetimes. The dominant model, the Unruh–DeWitt (UDW) detector, describes a pointlike particle interacting with a quantum field along a classical trajectory, with only the particle’s internal state treated as a quantum degree of freedom.

Recent studies have moved to include more realistic quantum effects, describing standard UDW detectors in superpositions of classical trajectories, or upgrading the model to better capture the properties of physical systems such as atoms, with a quantised centre of mass (CoM) dynamically evolving under a non-relativistic Hamiltonian, and the introduction of mass-energy equivalence.

In this work, we compare superpositions of the standard and quantum-CoM detector models, and explore under which limits and conditions one model can reasonably approximate the other. We indeed find regimes in which the quantum model approaches the classical, but also effects in the quantum-CoM case which the standard UDW model is not equipped to capture.

Carolyn Wood

Postdoctoral Scientist

Carolyn Wood is a postdoctoral researcher at the University of Queensland, in Brisbane, Australia focusing on quantum machine learning and physics at the interface between quantum mechanics and general relativity.