2020/05/31 by Joshua Foo, Sho Onoe, Robert B. Mann +1
Physics and Astronomy · #Causality (physics) #Classical mechanics #Cosmology and Gravitation Theories #Curvature #Detector #Noncommutative and Quantum Gravity Theories #Optics #Physics #Quantum #Quantum Electrodynamics and Casimir Effect #Quantum entanglement #Quantum field theory #Quantum mechanics #Spacetime #Superposition principle #Theoretical physics #Unruh effect #gr-qc #quant-ph
paper · pdf · doi:10.1103/physrevresearch.3.043056
published as Phys. Rev. Research 3, 043056 (2021) · 8 pages, 6 figures
openalex publication_date 2021/10/21 · arxiv created 2021/11/15 · arxiv updated 2021/11/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Particle detector models such as the Unruh--deWitt detector are widely used in relativistic quantum information and field theory to probe the global features of spacetime and quantum fields. These detectors are typically modeled as coupling locally to the field along a classical worldline. In this paper, we utilize a recent framework that enables us to prepare the detector in a quantum-controlled superposition of trajectories and study its response to a massless scalar field in finite-temperature Minkowski spacetime and an expanding de Sitter universe. Unlike a detector on a classical path, which cannot distinguish these spacetimes, the superposed detector can do so by acquiring nonlocal information about the geometric and causal structure of its environment, demonstrating its capability as a probe of these global properties.