A proximity-effect thermometer measures the temperature dependent critical supercurrent in a long superconductor normal metal superconductor (SNS) Josephson junction. Typically, the transition from the superconducting to the normal state is detected by monitoring the appearance of a voltage across the junction. We describe a new approach to detect the transition based on the temperature increas...

We consider a Josephson junction where the weak-link is formed by a non-centrosymmetric ferromagnet. In such a junction, the superconducting current acts as a direct driving force on the magnetic moment. We show that the a.c. Josephson effect generates a magnetic precession providing then a feedback to the current. Magnetic dynamics result in several anomalies of current-phase relations (second...

The fundamental noise limit of a phase-preserving amplifier at frequency [Formula: see text] is the standard quantum limit [Formula: see text]. In the microwave range, the best candidates have been amplifiers based on superconducting quantum interference devices (reaching the noise temperature [Formula: see text] at 700 MHz), and non-degenerate parametric amplifiers (reaching noise levels close...

We outline the basic concepts of the superconducting tunnel-junction detectors (STJs) and the performance limits. The state of present development is presented, along with projections for future developments. The performance approaches the limit due to intrinsic statistics for backtunneling devices, for photon energies E d 1 keV. The performance should soon approach those limits for energies ab...

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...

Inspired by recent experiments, we study a short superconducting junction of length L ξ (coherence length) inserted in a dc-SQUID containing an ancillary Josephson tunneling junction. We evaluate the nonequilibrium occupation of the Andreev bound states (ABS) for the case of a conventional junction and a topological junction, with the latter case of ABS corresponding to a Majorana mode. We take...

A normal-distribution-function-shaped superconducting tunnel junction (NDF-STJ) which consists of Nb/Al-AlOx/Al/Nb has been fabricated as an X-ray detector. Current voltage characteristics were measured at 0.4 K using three kinds of STJs, which have the dispersion parameters σ of 0.25, 0.45 and 0.75. These STJs showed very low subgap leakage current of about 5 nA. By irradiating with 5.9 keV X-...

The development of modular and versatile quantum interconnect hardware is a key next step in the scaling information platforms to larger size greater functionality. For superconducting systems, fast well-controlled tunable circuit couplers will be paramount for achieving high-fidelity resource-efficient connectivity, whether performing two-qubit gate operations, encoding or decoding data bus, i...

We demonstrate that a suspended nanowire forming a weak link between two superconductors can be cooled to its motional ground state by a supercurrent flow. The predicted cooling mechanism has its origins in magnetic field induced inelastic tunneling of the macroscopic superconducting phase associated with the junction. Furthermore, we show that the voltage drop over the junction is proportional...

We investigate hysteresis in the transport properties of superconductor-normal-metal-superconductor (S-N-S) junctions at low temperatures by measuring directly the electron temperature in the normal metal. Our results demonstrate unambiguously that the hysteresis results from an increase of the normal-metal electron temperature once the junction switches to the resistive state. In our geometry,...