Superconducting Parametric Amplifier for Astronomy and Quantum Computing

超导参量放大器（superconducting parametric amplifiers, SPAs）是一种新型的放大器技术，它的出现引起了天文学和量子计算界的广泛关注。这是因为spa可以在非常宽的带宽上实现量子限制的灵敏度。它们结构紧凑，易于用平面电路技术制造，具有超低的散热，并且可以直接与其他探测器电路集成。其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，以显着提高外差接收器的灵敏度，并且由于耗散可以忽略不计，因此可以构建大型放热阵列。它将对毫米/亚毫米天文学和b模式CMB实验产生巨大影响，这些实验研究宇宙的起源和恒星/行星的形成，符合STFC的核心计划。它们的大带宽、高功率处理和量子限制噪声性能将对量子计算架构产生深远影响，并提高处理数百量子比特（qubit）的保真度。这将开启建造实用量子计算机的真正可能性，这是UKRI通过英国国家量子技术计划投入巨资的一个活跃研究领域。本学生项目的目标是开发微波频率的量子限制SPA，取代传统的半导体放大器，因为它耗电且产生大量热量。最重要的是，这些半导体放大器无法达到许多先进应用所需的量子限制灵敏度。在这个项目中，学生将学习理论背景，并开发自己的仿真代码来模拟SPA，同时学习使用商业电磁学软件来设计放大器。然后，学生将有机会参与使用最先进的无尘室设备的设备制造，无论是在牛津，还是与我们的其他合作者（巴黎天文台）。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。特别地，学生将研究放大器的灵敏度和增益对温度和超导材料损耗的依赖。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技术还将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的低功耗要求和散热将允许构建具有宽视场和快速映射的大像素计数仪器。这对于功率和冷却能力有限的卫星通信系统非常重要。它们对于4/5G电信非常重要，其中已经开始讨论开发6G系统，以实现30-100 GHz链路运行的几TB/s，为最终用户提供更好的质量和更高的速度互联网。这对生物化学和制药研究是有益的，该地区丰富的化学线将允许探索许多系统中的复杂生物学和化学行为，有可能为癌症治疗等医疗问题找到新的药物和解决方案。已经有许多英国公司，如ETL和牛津仪器，对这一领域表达了浓厚的兴趣。

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.