Operating a contextual Stern-Gerlach apparatus

TL;DR

This paper introduces a cavity QED analogue of the Stern-Gerlach experiment, demonstrating how measurement influences quantum state stability and producing superpositions, with potential diagnostic tools for cavity field fluctuations.

Contribution

It presents a novel contextual cavity QED setup extending the Stern-Gerlach experiment, highlighting measurement effects on dressed states and quantum superpositions.

Findings

Self-consistent spontaneous dressed-state polarization emerges at low driving strength.

Persistent production of coherent-state superpositions under specific monitoring conditions.

Photoelectron emission statistics serve as a diagnostic for cavity field fluctuations.

Abstract

We propose a contextual cavity/circuit QED analogue and extension of the Stern-Gerlach experiment, where the pseudo-spin of a two-state `atomic' transition plays the role of the ``spin'', while the resonant field driving the transition stands for the ``magnetic field''. A phase-sensitive continuous detection of the cavity field coupled to the induced `atomic' dipole affects the stability of the two distinct outcomes. The dressed states comprising the latter give their place to a self-consistent spontaneous dressed-state polarization as the driving strength is lowered. The associated evolution proves anew highly contextual, underpinned by a persistent production of coherent-state superpositions for a particular setting of the monitoring device. Finally, when bistability is absent, we employ the photoelectron `atomic' emission statistics as a diagnostic tool of the cavity field fluctuations.