Dresden 2014 – scientific programme

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PV: Plenarvorträge

PV IV

PV IV: Plenary Talk

Tuesday, April 1, 2014, 08:30–09:15, HSZ 01

Coherent Mechanics: Tuning and Playing an Electric Nano-Guitar — •Jörg P. Kotthaus — Center for NanoScience and Fakultät für Physik, LMU München, Germany

Nanomechanical resonators operating with high quality factors Q = f/Δf at radio frequencies f in the 10 MHz regime gain importance as sensors for smallest masses, forces, and displacements, but also as potential devices for coherent information processing. With tightly stretched nanostrings of silicon nitride exhibiting Q-factors up to 1 million, relevant damping mechanisms limiting Q are explored. Combining electric gradient field actuation with microwave-cavity-assisted motion detection provides a completely electrically controlled platform to study the coherent dynamics of nanoscale resonators over a wide temperature range. Coherent control in the non-linear excitation regime is utilized to induce fast switching between bistable states.

Coupling two orthogonal transverse resonance modes via gradient fields creates a classical analogue of a quantized two-level system and is studied in its coherent motion. With Landau-Zener-type experiments one can explore the transition from adiabatic to diabatic behavior. Pulsed excitation experiments investigate the coherent dynamics on a Bloch-like energy sphere and yield classical equivalents of Rabi oscillations, Ramsey fringes, and Hahn echoes, which further illuminate mechanisms of decoherence. With the quantum regime of mechanics now becoming accessible such resonators might eventually become useful for information processing with true quantum mechanical features.