Quantum stochastic resonance of individual Fe atoms

Prof. Susan Coppersmith, Head of School of Physics, University New South Wales (UNSW), FLEET Associate Investigator, Research Theme 1: Topological Dissipationless Systems.

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Stochastic resonance, where noise synchronizes a system’s response to an external drive, is a phenomenon that occurs in a wide variety of noisy systems ranging from the dynamics of neurons to the periodicity of ice ages. This talk will present theory and experiments on a quantum system that exhibits stochastic resonance — the quantum tunneling of the magnetization of a single Fe atom measured using spin-polarized scanning tunneling microscopy. Stochastic resonance is shown deep in the quantum regime, where fluctuations are driven by tunneling of the magnetization, as well as in a semi-classical crossover region where thermal excitations set in. An analytic theory with no adjustable parameters agrees quantitatively with experiment, and provides a path towards probing dynamics on time scales shorter than can be resolved experimentally.

Professor Coppersmith is a theoretical condensed matter physicist who has made substantial contributions to the understanding of a broad range of subjects, including glasses, biominerals, granular materials, and quantum computers. Her current research focus is on the development of quantum computers using silicon technology similar to that used in modern classical computers, with a particular focus on the use of silicon/silicon-germanium heterostructures.

Her honors include fellowship in the Australian Academy of Science, the Australian Institute of Physics, and the Royal Society of New South Wales, as well as the American Physical Society, the American Association for the Advancement of Science, and the American Academy of Arts and Sciences, and membership in the National Academy of Sciences of the United States.

This talk is part of an ongoing series of talks by US and Australian researchers presenting novel developments in condensed matter and cold atomic physics, enriching connections between the two physics communities. Co-presented by FLEET, Monash School of Physics and Astronomy, and the Joint Quantum Institute.

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