An Introduction to Parametric Amplifiers for Superconducting Quantum Information

Historically, parametric amplifiers were the premier technology for ultra-low noise microwave amplification before the advent of masers and HEMTs, so why have they seen a resurgence in today’s quantum computing efforts? The answer has to do with the unique constraints associated with measurement of superconducting microwave quantum circuits: limited cooling power and the requirement for nearly-quantum-limited noise performance. In this talk, I will give an overview of how parametric amplification works, including simple examples implemented with superconducting circuits. In addition, I will discuss some of the unique challenges of characterizing these amplifiers and using them in a practical context. To this end, I will outline particular near-term opportunities for improving bandwidth, noise performance, and usability.