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Controlling Electron-Phonon Interaction in Nanocircuits — Strong Coupling Regime

Fig 1. Top: Scanning electron micrograph of the (001) surface (light gray) of a GaAs wafer. Metal gates (dark) shape a microwave surface acoustic wave (SAW) cavity. Bottom: AFM contact mode lock-in measurement of a 3 GHz standing SAW centered in the cavity.

This project aims at the realization of hybrid quantum systems based on the coupling of single electrons and single phonons in the form of acoustic waves in tailored nanostructures (see figure). Our focus is the study of the electron-phonon interaction in systems consisting of electrostatic quantum dots placed in a high-quality phonon resonator aiming at reaching the strong coupling regime. 

The coherent interaction between a single electron and a single phonon in such a structure will give rise to quantum hybrid states useful for quantum information applications. These states resemble those observed in circuit quantum electrodynamics, but now with a phonon replacing the microwave photon. As compared to photons, phonons have the advantage of much smaller wavelengths such that they can be matched to the size of a nanostructure to enhance the electron-phonon coupling as compared to the electron-photon coupling at the relevant energies. Phonons will also be used to couple distant qubits: they are advantageous for the remote coupling since their mean-free-path or coherence are expected to be longer than those of electronic excitations in nanostructures.

This project is a collaboration between the Paul-Drude-Institute and the Free University of Berlin supported by the Deutsche Forschungsgemeinschaft (DFG) via the DFG grant "Controlling Electron-Phonon Interaction in Nanocircuits — Strong Coupling Regime”.


Selected Publications

  1. Title

    Scanning X-ray diffraction microscopy of a 6 GHz surface acoustic wave

    M. Hanke, N. Ashurbekov, E. Zatterin, M.E. Msall, J. Hellemann, P. V. Santos, T.U. Schulli, S. Ludwig
    Phys. Rev. Appl., 19, 024038-1 (2023)
    10.1103/PhysRevApplied.19.024038 (PDI-ID: 2837)
  2. Title

    Determining amplitudes of standing surface acoustic waves via atomic force microscopy

    J. Hellemann, F. Müller, M. Msall, P. V. Santos, S. Ludwig
    Phys. Rev. Appl., 17, 044024 (2022)
    10.1103/PhysRevApplied.17.044024 (PDI-ID: 2833)
  3. Title

    Acoustic field for the control of electronic excitations in semiconductor nanostructures

    P. V. Santos, M. Msall, S. Ludwig
    IEEE, Proceedings of the 2018 Ultrasonic Symposium, 1 (2018)
    10.1109/ULTSYM.2018.8579769 (PDI-ID: 2648)