Fast sample-exchange cryogenic microwave characterization apparatus

• Subject Area: Condensed Matter Physics
• Term: Funded in 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 448792623

The aim of this research project is to efficiently improve solid-state based quantum systems operating at microwave frequencies and at cryogenic temperatures. To make highly sensitive quantum systems useful for quantum computing, quantum communication or quantum sensing the influence of noise and disturbances must be reduced to an absolute minimum. The fabrication and control of resonators, quantum bits, coupling elements, amplifiers or other quantum systems with high quality and the understanding of the coherence-limiting factors are, therefore, of immense importance for further quantum technological applications. The characterization and the efficient improvement is, however, severely hindered by the relatively long turnaround time that is required to cool down, to measure and to warm up devices.In this project, we aim to improve the quality and control of both superconducting quantum circuits and of hybrid quantum systems, which combine different microscopic degrees of freedom (phonons, magnons, plasmons, photons) and different materials. To reach the project goals, a low-temperature microwave apparatus is required that enables a fast sample exchange and that covers a wide frequency range. The system applied for consists of a dilution refrigerator with a bottom-loading mechanism, which significantly increases the characterization throughput by enabling samples to be cooled to a base temperature of 10-20mK within a few hours. The cooling capacity, the sample volume and the wiring of the cryostat are designed to enable the characterization of various quantum systems in a frequency range up to 40GHz. For the time-resolved control and homodyne-based measurement, fast arbitrary wave generators (AWGs) and microwave signal sources, as well as an AWG/digitizer measuring unit together with low-temperature microwave components (low-noise amplifiers, circulators and isolators) are required. A wideband vector signal analyzer with four channels is planned for the rapid characterization of the frequency response and the simultaneous measurement of input/output relations of the samples.The measurement system will be installed at the Walther-Meißner-Institute and will be operated by the group of Stefan Filipp. Other groups from the institute and as well as groups in the wider research network (Cluster of Excellence, TUM institutes) will be provided access to the system.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Tieftemperatur-Mikrowellenmessapparatur für schnellen Probenaustausch
• Instrumentation Group: 8550 Spezielle Kryostaten (für tiefste Temperaturen)
• Applicant Institution: Technische Universität München (TUM)
• Leader: Professor Dr. Stefan Filipp