Superconducting Parametric Amplifier for Astronomy and Quantum Computing

一种新型的放大器技术--超导参数放大器(SPA)的出现引起了天文学和量子计算界的极大关注。这是因为SPA可以在非常宽的带宽上实现量子受限的灵敏度。它们结构紧凑，易于采用平面电路技术制作，具有超低的散热，可以直接与其他探测器电路集成。它们的性能远远优于目前天文学和量子计算实验中使用的最先进的低温低噪声放大器。因此，这些设备可以彻底改变天文学和量子信息技术中的超灵敏仪器，从微波到亚毫米(亚毫米)波长。特别是，它们可以用作读出放大器，以显著提高外差接收器的灵敏度，并能够由于可以忽略的耗散而构造大型测辐射热阵列。它将在毫米/亚毫米天文学和符合STFC核心计划的研究宇宙起源和恒星/行星形成的B型CMB实验中产生巨大影响。它们的大带宽、高功率处理和量子受限噪声性能将对量子计算体系结构产生深远影响，并提高处理数百个量子比特(Qbit)的保真度。这将为建立实用的量子计算机打开真正的可能性，这是一个活跃的研究领域，英国国家量子技术研究所通过英国国家量子技术计划在这个活跃的研究领域投入了大量资金。这个学生项目的目标是开发一种微波频率的量子受限SPA，用大量的热量产生取代耗电的传统半导体放大器。最重要的是，这些半导体放大器无法达到许多先进应用中所需的量子有限灵敏度。在这个项目中，学生将学习理论背景并开发自己的模拟代码来模拟SPA，同时学习使用商业电磁软件来设计放大器。然后，学生将有机会使用牛津大学最先进的洁净室设施或与我们的其他合作者(巴黎天文台)一起参与设备的制造。学生还将学习如何使用亚开尔文低温系统和其他实验技术来测量放大器的性能。特别是，学生将研究放大器的灵敏度和增益对熔池温度和超导材料损耗的依赖关系。最后，学生将把放大器集成到现有的天文接收器/量子计算接收器中，并评估对接收器性能的影响。除了学术研究外，SPA技术将具有巨大的潜力为商业应用提供解决方案，如4/5G电信、卫星系统、量子信息技术和生物化学/制药行业。SPA的低功耗和散热性将使构建大视场和快速映射的大像素数仪器成为可能。这对于功率和冷却能力有限的卫星通信系统来说很重要。它们对4/5G电信很重要，已经开始讨论开发6G系统，以实现几TB/S的链路在30-100 GHz运行，为最终用户提供更好的质量和更快的互联网。它有利于生物化学和制药研究，该地区丰富的化学线将使人们能够探索许多系统中复杂的生物和化学行为，有可能找到新药和癌症治疗等医学问题的解决方案。已有许多英国公司，如ETL和牛津仪器公司，对这一领域表示出浓厚兴趣。

The emergence of a new type of amplifier technology, the superconducting parametric amplifiers (SPAs), had drawn considerable attention from the astronomical and quantum computing communities. This is because SPAs can achieve quantum-limited sensitivity over a very broad bandwidth. They are compact, easy to fabricate with planar circuit technology, have ultra-low heat dissipation, and can be integrated directly with other detector circuits. Their performance is far superior to the state-of-the-art cryogenic low noise amplifier used currently in astronomy and quantum computing experiments. These devices therefore can revolutionise ultra-sensitive instrumentation in astronomy and quantum information technologies, from microwave to sub-millimetre (sub-mm) wavelengths. In particular, they can be used as readout amplifiers to improve the heterodyne receiver sensitivity significantly, and enable the construction of large bolometric arrays as a result of the negligible dissipation. It will have a huge impact in mm/sub-mm astronomy & B-mode CMB experiments which study the origin of the Universe and the stars/planet formation that is in line with STFC's core programme.Their large bandwidth, high power handling and quantum-limited noise performance will have profound effect on quantum computing architecture and improve the fidelity to process hundreds of quantum bits (qubit). This will open up the real possibility of building a practical quantum computer, an active research area where UKRI have invested heavily on through the UK National Quantum Technology Programme.The aim of this student project is to develop a quantum-limited SPA at microwave frequencies, replacing the traditional semiconductor amplifiers which are power hungry with substantial heat generation. Most importantly, these semiconductor amplifiers are unable to achieve the quantum limited sensitivity required in many advance applications. In this project, the student will study the theoretical background and develop his own simulation code to model the SPA, along with learning to use commercial electromagnetism software to design the amplifiers. The student will then have the chance to get involve in the fabrication of the devices using state-of-the-art clean room facilities, either here in Oxford, or with our other collaborators (Observatory of Paris). The student will also learn how to use sub-Kelvin cryogenics system and other experimental techniques, for measuring the performance of the amplifiers. In particular, the student will investigate the amplifier sensitivity and gain dependence on bath the temperature and on the losses of superconducting materials. Finally, the student will integrate the amplifier into an existing astronomical receiver/quantum computing receiver and assess the impact on the receiver performance.Apart from academic research, SPA technology will have great potential to provide solutions for commercial applications such as 4/5G telecommunication, satellite systems, quantum information technology and biochemistry/pharmaceutical industries as well. The low power requirement and heat dissipation of the SPA will allow the construction of large pixel-count instrument with wide field and fast mapping. This is important for satellite communication systems that have limited power and cooling capability. They are important for 4/5G telecommunication, where discussions have already begun to develop 6G systems to achieve several TB/s with link operating at 30-100 GHz, providing better quality and higher speed internet to end users. It is beneficial for biochemistry and pharmaceutical research, where the wealth of chemistry lines in this region will allow probing of complex biology and chemistry behaviour in many systems, potentially finding new drugs and solution for medical issues such as cancer treatment. There are already many UK companies such as ETL and Oxford Instrument that have express intense interest in this field.