A1 Refereed original research article in a scientific journal
Synchronization effects in a periodically driven two-level system
Authors: Settimo, Federico; Vacchini, Bassano
Publisher: American Physical Society (APS)
Publication year: 2026
Journal: Physical Review A
Article number: 022213
Volume: 113
Issue: 2
ISSN: 2469-9926
eISSN: 2469-9934
DOI: https://doi.org/10.1103/cswq-l3c8
Publication's open availability at the time of reporting: No Open Access
Publication channel's open availability : Partially Open Access publication channel
Web address : https://doi.org/10.1103/cswq-l3c8
Preprint address: https://arxiv.org/abs/2511.04339
We study phase synchronization in a driven two-level system coupled to a non-Markovian bosonic reservoir. The dynamics is described by treating the system-bath coupling and the coherent drive without invoking the rotating-wave approximation, and simulated using the numerically exact hierarchical equations of motion. We observe that a robust phase locking develops and that the corresponding synchronization measure rapidly acquires a finite value when the system is tuned to what we identify as a resonant-ratio condition, namely, when the ratio between the drive amplitude and its frequency coincides with a zero of the Bessel function J0. We provide an explanation for this phenomenon by means of a static approximation derived from a Fourier analysis of the periodically driven Hamiltonian.
Funding information in the publication:
F.S. acknowledges support from Magnus Ehrnroothin Saeaetioe. B.V. acknowledges support from MUR and Next Generation EU via the PRIN 2022 Project "Quantum Reservoir Computing (QuReCo) " (Contract No. 2022FEXLYB) and the NQSTI-Spoke1-BaC project QuSynKrono (Contract No. PE00000023-QuSynKrono) .
