Practical, high dynamic range parametric amplification with RF SQUID arrays
High-fidelity qubit readout, which is critical for error correction in large-scale quantum computers, requires a short and strong pulse transiting the qubit’s measurement mode which is then processed by a necessarily high bandwidth, high saturation power, quantum-limited amplifier; with frequency multiplexing expanding the required bandwidth by the number of channels to be amplified. In this talk, I will present some of my dissertation research in optimizing saturation power in single-mode parametric amplifiers based on radio frequency Superconducting QUantum Interference Device (rf-SQUID) arrays with modest bandwidth (~50 MHz). Then, building on work that demonstrates broadband resonant parametric amplifiers, I will explore some of the challenges in pumping an amplifier with fractional bandwidth in excess of 15 percent. I will also discuss some challenges in scaling readout with reflection parametric amplifiers, and justify the need for matched, directional amplification that can be integrated nearer to the qubit’s measurement mode. Lastly, as a step toward a solution to this challenge in scaling readout to larger processors, I will show a method for optimizing the scattering parameters of a broadband, matched, directional parametric amplifier with only six resonant modes.
Livestream the event on zoom (Yale login required)