Fast sample-exchange cryogenic microwave characterization apparatus

这一研究项目的目的是有效地改进工作在微波频率和低温下的基于固态的量子系统。为了使高度敏感的量子系统用于量子计算、量子通信或量子传感，必须将噪声和干扰的影响降低到绝对最小。因此，高质量的谐振器、量子比特、耦合元件、放大器或其他量子系统的制造和控制，以及对相干限制因素的了解，对于进一步的量子技术应用具有极其重要的意义。然而，冷却、测量和预热器件所需的相对较长的周转时间严重阻碍了表征和效率的提高。在这个项目中，我们的目标是提高超导量子电路和混合量子系统的质量和控制，这些混合量子系统结合了不同的微观自由度(声子、磁子、等离子、光子)和不同的材料。为了实现项目目标，需要一种能够快速交换样品并覆盖较宽频率范围的低温微波设备。所申请的系统包括一个带有底部装载机制的稀释冰箱，它使样品能够在几个小时内冷却到10-20mK的基温，从而显著提高了表征吞吐量。低温恒温器的冷却能力、样品体积和布线设计使其能够在高达40 GHz的频率范围内表征各种量子系统。对于时间分辨控制和基于零差的测量，需要快速任意波发生器(AWG)和微波信号源，以及AWG/数字化测量单元和低温微波组件(低噪声放大器、环行器和隔离器)。为了快速表征样品的频率响应和同时测量样品的输入/输出关系，计划设计一台四通道宽带矢量信号分析仪。测量系统将安装在Walther-Meiüner研究所，由Stefan Filipp集团运营。研究所的其他小组以及更广泛的研究网络中的小组(英才小组、TUM研究所)将被允许进入该系统。

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.