SPA4AstroQIT · Broadband Quantum-Limited Parametric Amplifier for Astronomy and Quantum Information Technology

The emerging technology of superconducting parametric amplifiers (SPAs) can achieve quantum-limited sensitivity over broad bandwidth, by utilising the wave-mixing mechanism in a passive nonlinear transmission medium. 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 performances are far superior to the state-of-the-art high electron mobility transistor (HEMT) amplifier, and they can operate from radio to THz frequencies. Therefore, they could potentially revolutionise almost every kind of microwave, millimetre (mm) and sub-millimetre (sub-mm) instrumentation: from observational astronomy to quantum information experiments. Their deployment as readout amplifiers could improve the heterodyne receiver sensitivity significantly, and enable the construction of large bolometric arrays. Their large bandwidth, high power handling and quantum-noise performance could have profound effect on quantum computing architecture, improve the fidelity to process hundreds of quantum bits (qubit). They can be used as front-end high frequency amplifiers operating at THz frequencies, which is hard to achieve with HEMT technology. In this proposal, I aim to develop: 1) ultra-broadband readout amplifiers for mm/sub-mm astronomical receivers and qubit experiments, which would enable the construction of large pixel-count system; 2) front-end amplifiers at mm frequencies for heterodyne receivers and B-mode Cosmic Microwave Background experiments; and 3) parametric frequency down-converter with positive conversion gain to replace Superconductor-Insulator-Superconductor (SIS) as ultra-low noise heterodyne mixer for large array application. The successful development of these programmes not only could transform the mm/sub-mm instrumentation in the future, but could also have huge impact on many other fields such as telecommunications, medical and quantum computing technology.