From classical to quantum stochastic resonance

Abstract

The open quantum system presented by atomic spins on surfaces is a unique platform to investigate the interplay between stochastic and deterministic behavior. This work investigates this interplay at the transition from classical to quantum behavior in tailored magnetic nanostructures. The structures are assembled with Fe atoms on a Cu2N surface grown on Cu(100) by using atom manipulation with a cryogenic-temperature scanning tunneling microscope. The spin state of the structures can be resolved with a spin-polarized tip, allowing their dynamic response to be measured. The stochastic evolution of the spin states is brought into a resonant regime by means of either a modulated exchange field or a modulated voltage applied with the tip. Undergoing this stochastic resonance yields insight into how these structures interact with their environment, with clear signatures of classical, semi-classical and quantum behavior being observed. This work sets the stage for a new way of interacting with incoherently evolving spin systems, by synchronizing their dynamics, and tailoring their interaction with their environment.