Superconducting Circuits without Inductors Based on Bistable Josephson Junctions

Thermal Activation of Superconducting Josephson Junctions

Superconducting quantum circuits (SQCs) are being explored as model systems for scalable quantum computing architectures. Josephson junctions are extensively used in superconducting quantum interference devices (SQUIDs) and in persistent-current qubit systems. Noise excitations, however, have a critical influence on their dynamics. Thus, the primary focus of this research was to investigate the...

Optimized fabrication process for nanoscale Josephson junctions used in superconducting quantum circuits

Microwave photon counter based on Josephson junctions.

We describe a microwave photon counter based on the current-biased Josephson junction. The junction is tuned to absorb single microwave photons from the incident field, after which it tunnels into a classically observable voltage state. Using two such detectors, we have performed a microwave version of the Hanbury Brown-Twiss experiment at 4 GHz and demonstrated a clear signature of photon bunc...

Josephson effect in small - area superconducting tunnel junctions at 604

We have measured the ac Josephson effect in small-area superconducting tunnel junctions at 604 GHz (A = 496pm) using a resonant planar dipole antenna to couple the radiation into the junction. In a 176-fl junction, we have observed up to the 7th Josephson step (at 8.75 m V), a performance comparable to that seen in point contacts. We also compare our data with the results of the RSJ model and o...

Quantum charge diffusion in underdamped Josephson junctions and superconducting nanowires

The effect of quantum fluctuations on the current-voltage characteristics of Josephson junctions and superconducting nanowires is studied in the underdamped limit. Quantum fluctuations induce transitions between a Coulomb–blockade and a supercurrent branch, and can significantly modify the shape of current-voltage characteristics in the case of a highly resistive environment. Owing to the phase...