Speaker
Description
Superconducting circuits are a promising platform for fault-tolerant quantum computing, quantum-limited amplification, ultra-low-power electronics, and sensors with ultimate sensitivity. Reducing loss and fabrication complexity in these circuits is therefore of significant interest.
Superinductors — superconducting inductors with impedances exceeding the resistance quantum — enable the development of protected qubits and enhance coupling to systems with small electric dipole moments. While Josephson-junction chains are a common approach, superinductors can also be realized using traces of disordered nanocomposite superconductors, such as granular aluminum (grAl). We explore the limits of impedance in grAl ring resonators, demonstrating inductances up to 4 μH and impedances exceeding 100 kΩ in the technologically relevant 4–8 GHz range. Despite these high impedances, the resonators maintain quality factors on the order of 10^5, making them well-suited for quantum information processing. Notably, they are fabricated in a single-step, zero-angle e-beam lift-off lithography process.