A comprehensive study of the dc and rf electrodynamic properties of YBa 2 Cu 307-, (YBCO) thin films, grain boundaries and Josephson junctions (JJ) is presented. The surface impedance Z, = R, + iX, of YBCO thin films is shown to have a dependence on rf current, which leads to nonlinear power losses at levels of rf power that are relevant for device applications. To understand the loss mechanism...

We have measured the supercurrent flowing through a nonhysteretic, ultrasmall, voltage-biased Josephson junction. In contrast with experiments performed so far on hysteretic Josephson junctions, we find a supercurrent peak whose maximum I(s max) increases as the temperature T decreases. The asymptotic T = 0 value of I(s max) agrees with the junction Ambegaokar-Baratoff critical current, as pred...

We propose the implementation of a Josephson radiation comb generator (JRCG) based on an extended Josephson junction subject to a time dependent magnetic field. The junction critical current shows known diffraction patterns and determines the position of the critical nodes when it vanishes. When the magnetic flux passes through one of such critical nodes, the superconducting phase must undergo ...

Quantum mechanics consideration, supported by a concrete example, yielded standard sources of direct voltage measured frequency (which is the most accurate measurable physical quantity) and extremely sensitive instrument for measuring magnetic induction SQUID an acronym based on term Superconducting Interference Device). The possibility these measurements Josephson junction. In this paper, infl...

The concept of thermophase refers to the appearance of a phase gradient inside a superconductor originating from the presence of an applied temperature bias across it. The resulting supercurrent flow may, in suitable conditions, fully counterbalance the temperature-bias-induced quasiparticle current therefore preventing the formation of any voltage drop, i.e., a thermovoltage, across the superc...

We describe the design for a scalable, solid-state quantum-information-processing architecture based on the integration of GHz-frequency nanomechanical resonators with Josephson tunnel junctions, which has the potential for demonstrating a variety of singleand multi-qubit operations critical to quantum computation. The computational qubits are eigenstates of large-area, currentbiased Josephson ...

Noise and decoherence are major obstacles to the implementation of Josephson junction qubits in quantum computing. Recent experiments suggest that two-level systems TLS in the oxide tunnel barrier are a source of decoherence. We explore two decoherence mechanisms in which these two-level systems lead to the decay of Rabi oscillations that result when Josephson junction qubits are subjected to s...

We have fabricated two-dimensional (2D) small-Josephson-junction arrays of which each Al-AlOx-Al junction is shunted by a Cr resistor. The arrays with large junction resistance and large charging energy show a transition from insulating to superconducting behavior when the shunt resistance is lowered below a critical value, which is close to 2R(Q) ( R(Q) identical withh/4e(2) = 6.45 kOmega). Th...