Quantum-Limited Superconducting Microwave Amplifiers

Quantum-limited parametric amplifiers are devices which can boost the strength of a signal whilst only adding the minimum amount of noise required by quantum mechanics. Typically, parametric amplifiers are made by placing a lossless nonlinear element inside a cavity, or by creating long transmission lines with many instances of the nonlinearity (so called traveling wave amplifiers). Traveling wave geometries are attractive, since they offer amplification over wide frequency ranges, as opposed to cavity amplifiers which operate within a narrow resonant band. State-of-the-art traveling wave amplifiers in the microwave domain can use Josephson junctions as the nonlinear element, or the kinetic inductance intrinsic to thin superconducting films.

Kinetic inductance traveling wave amplifiers have gained much attention recently, since they provide near-quantum-limited noise performance and exhibit dynamic ranges that are several orders of magnitude larger than their Josephson junction counterparts. This opens up many exciting possibilities, from multiplexed readout of large qubit arrays in quantum computers, to quantum-limited spin resonance spectroscopy. However, kinetic inductance amplifiers suffer from long physical lengths, ranging from tens of centimeters to several meters long, which poses significant fabrication and experimental challenges.

This project aims to miniaturize kinetic inductance traveling wave parametric amplifiers, reducing dimensions down to those only typically seen in Josephson junction devices. This will provide compact amplifiers and also allow them to operate at RF frequencies, which is of particular interest to experiments in quantum computing and NMR.

How to Apply

Express your interest in this project by emailing Associate Professor Jarryd Pla. Include a copy of your CV and your academic transcript(s).