Motherboard for superconducting qubit readout
The capability to perform rapid, high-fidelity, quantum non-demolition measurements is a critical requirement of quantum computers. State-of-the-art superconducting quantum computers achieve this requirement by incorporating multiple microwave components in their output chain, such as Purcell filters, cryogenic circulators and isolators, and quantum limited amplifiers. However, applying such a readout scheme on a large scale is challenging, mainly because cryogenic circulators and isolators rely on magnetic materials and strong magnetic fields, which limit their miniaturization, proximity to the quantum processor, and their direct integration with other components. To solve this problem, we develop nonreciprocal Josephson devices  that could replace magnetic circulators and isolators and form in combination with other on-chip components, scalable motherboards for qubit readout .  B. Abdo et al., Nat. Commun. 2019.  B. Abdo et al., arXiv 2020.