Macroscopic Quantum Systems as Probes of Casimir Physics and Graviton Signatures

by Germain Tobar (Stockholm University)

Friday 8 May 2026, 13:00 → 15:00 Europe/Stockholm

AlbaNova A5:1041 - CoPS grupprum (AlbaNova Main Building)

Abstract:
“Over the past few decades, advances in light–matter control have enabled quantum
phenomena to be prepared and measured at increasingly large mass scales. In this thesis, we
show that single gravitons can, in principle, be detected by developing quantum-optical
models for the interaction of quantized gravitational radiation with matter. We demonstrate
that resonant-mass and interferometric gravitational-wave detectors, when read-out in the
particle-number basis, operate as the gravitational analogue of a photoelectric detector:
discrete energy absorption events and resonance conditions enable single-quantum
exchange to be identified, with detector efficiency defined by the ratio of the absorbed to
incident gravitons. While graviton emission from microscopic systems is negligibly slow
(supporting Dyson’s pessimistic conjecture), macroscopic resonators benefit from enhanced
rates of energy exchange. Finally, we revisit the dynamical Casimir effect, arguing that all
existing demonstrations to date admit an interpretation as parametric mode coupling of
static cavity modes (the same physics that underlies many standard quantum optics
experiments), and we propose a near-term route to witnessing Moore’s original effect using
atomic arrays as quantum mirrors that can map the effect onto a measurable frequency shift
of a Rydberg control atom.’’