Superconducting Parametric Amplifier for Astronomy and Quantum Computing

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.