Engineering the quantum computer: a case study of the circulator

Continuous advancements in the performance of solid state qubits makes
it likely that experimentalists will try to make scalable quantum
information processing structures in the coming years. Many
improvements will be needed in the instrumentation of these devices;
here we will focus on the electric circulator, as essential component
for high-fidelity qubit measurements using microwaves. The current
ferrite cirulators are unchanged since around 1960; time is ripe for a
fundamental improvement in these devices. I will argue that new
understanding of plasmonic excitations in quantum-Hall structures could
provide such an improvement.