Regensburg 2025 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 11: Superconductivity: Poster

TT 11.49: Poster

Monday, March 17, 2025, 15:00–18:00, P4

Enhancement of Low Temperature Dielectric Loss through Vibrational Bias — •Jonathan Herbrich, Christian Ständer, Andreas Fleischmann, Andreas Reiser, and Christian Enss — Kirchhoff Institute for Physics, Heidelberg University

At low temperatures low energy excitations are present in amourphous solids, due to atomic tunneling systems (TSs), leading to different properties compared to their crystalline counterparts. These TSs can be expressed as two level systems with a flatly distributed energy splitting. These properties are well described by the phenomenological standard tunneling modell (STM). Due to their negative influence like noise and decoherance on superconducting quantum devices, these TSs are a subject of recent investigations.
Lately we investigated the dielectric rf-response of an amourphous sample while slowly varying an electric bias field. A microfabricated superconducting LC-resonator, using the sample as a substrate, was used for these measurements. In recent measurements a mechanical strain field was used instead of the electric one. The field is applied by bending the sample with a piezoelectric actuator. As a result, the energy splitting of the TSs is modified, as these couple to the strain field via the deformation potential. Our measurements can be described in a framework based on Landau-Zener transition, origianally developed for the description of electrically biased resonators.

Keywords: Superconduction Resonator; Two Level System; Non-linear Dynamics; Decoherance and Noise; Mechanical Strain Field