Regensburg 2025 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 55: Superconducting Electronics: SQUIDs, Qubits, Circuit QED III

TT 55.11: Talk

Friday, March 21, 2025, 12:15–12:30, H36

Demonstration of a Solid-State Random Defect Maser — •Christian Ständer, Jan Blickberndt, Andreas Fleischmann, Andreas Reiser, and Christian Enss — Kirchhoff Institute for Physics, Heidelberg University

The low temperature properties of amorphous solids are governed by atomic tunneling systems, which can be described as two-level systems (TLS) with a distribution of their energy splitting E, as assumed by the phenomenological standard tunnelling model. Recent interest in these systems due to their deteriorative effects on the performance of superconducting quantum devices lead to experimental investigations of atomic tunnelling systems.
We designed and microfabricated a superconducting LC-resonator to study the dielectric rf-response of an amorphous sample in the presence of a slowly varying electric bias field and two symetrically detuned pump tones. A novel method of applying this electrical bias field was introduced to the resonators. By shifting the energy splitting of the inverted TLS with the external bias, to match the resonators frequency we found a paramterspace of negative dielectric loss, hence gain. In this way we demonstrate that a media containing random TLS could be transformed from an inertially lossy system to a system that features no significant dielectric loss, up to a point of coherent gain.

Keywords: Superconducting Resonator; Two Level System; Random Defect Maser