An interconnect may have a first end coupled to a superconducting system and a second end coupled to a non-superconducting system. The interconnect may include a superconducting element having a critical temperature. During operation of the superconducting system and the non-superconducting system, a first portion of the interconnect near the first end may have a first temperature equal to or below the critical temperature of the superconducting element, a second portion of the interconnect near the second end may have a second temperature above the critical temperature of the superconducting element, and the interconnect may further be configured to reduce a length of the second portion such that temperature substantially over an entire length of the interconnect is maintained at a temperature equal to or below the critical temperature of the superconducting element.

In various embodiments, superconducting wires incorporate diffusion barriers composed of Ta alloys that resist internal diffusion and provide superior mechanical strength to the wires.

An interconnect may have a first end coupled to a superconducting system and a second end coupled to a non-superconducting system. The interconnect may include a superconducting element having a critical temperature. During operation of the superconducting system and the non-superconducting system, a first portion of the interconnect near the first end may have a first temperature equal to or below the critical temperature of the superconducting element, a second portion of the interconnect near the second end may have a second temperature above the critical temperature of the superconducting element, and the interconnect may further be configured to reduce a length of the second portion such that temperature substantially over an entire length of the interconnect is maintained at a temperature equal to or below the critical temperature of the superconducting element.

Systems and devices for providing differential input/output communication with a superconducting device are described. Each differential I/O communication is electrically filtered using a respective tubular filter structure incorporating superconducting lumped element devices and high frequency dissipation by metal powder epoxy. A plurality of such tubular filter structures is arranged in a cryogenic, multi-tiered assembly further including structural/thermalization supports and a device sample holder assembly for securing a device sample, for example a superconducting quantum processor. The interface between the cryogenic tubular filter assembly and room temperature electronics is achieved using hermetically sealed vacuum feed-through structures designed to receive flexible printed circuit board cable.

A technique relates a superconducting microwave cavity. An array of posts has different heights in the cavity, and the array supports a localized microwave mode. The array of posts includes lower resonant frequency posts and higher resonant frequency posts. The higher resonant frequency posts are arranged around the lower resonant frequency posts. A first plate is opposite a second plate in the cavity. One end of the lower resonant frequency posts is positioned on the second plate so as to be electrically connected to the second plate. Another end of the lower resonant frequency posts in the array is open so as not to form an electrical connection to the first plate. Qubits are connected to the lower resonant frequency posts in the array of posts, such that each of the qubits is physically connected to one or two of the lower resonant frequency posts in the array of posts.

A technique relates a superconducting microwave cavity. An array of posts has different heights in the cavity, and the array supports a localized microwave mode. The array of posts includes lower resonant frequency posts and higher resonant frequency posts. The higher resonant frequency posts are arranged around the lower resonant frequency posts. A first plate is opposite a second plate in the cavity. One end of the lower resonant frequency posts is positioned on the second plate so as to be electrically connected to the second plate. Another end of the lower resonant frequency posts in the array is open so as not to form an electrical connection to the first plate. Qubits are connected to the lower resonant frequency posts in the array of posts, such that each of the qubits is physically connected to one or two of the lower resonant frequency posts in the array of posts.

The various embodiments described herein include methods, devices, and systems for fabricating and operating transistors. In one aspect, a transistor includes: (1) a semiconducting component configured to operate in an on state at temperatures above a semiconducting threshold temperature; and (2) a superconducting component configured to operate in a superconducting state while: (a) a temperature of the superconducting component is below a superconducting threshold temperature; and (b) a first current supplied to the superconducting component is below a current threshold; where: (i) the semiconducting component is located adjacent to the superconducting component; and (ii) in response to a first input voltage, the semiconducting component is configured to generate an electromagnetic field sufficient to lower the current threshold such that the first current exceeds the lowered current threshold, thereby transitioning the superconducting component to a non-superconducting state.

A superconducting material includes YBa.sub.2Cu.sub.3O.sub.7-? and a nano-structured, preferably nanowires, WO.sub.3 dopant in a range of from 0.01 to 3.0 wt. %, preferably 0.075 to 0.2 wt. %, based on total material weight. Methods of making the superconductor may preferably avoid solvents and pursue solid-state synthesis employing Y, Ba, and/or Cu oxides and/or carbonates.

The present invention addresses a problem of providing an MgB2 wire material having a small reversible bending radius, a superconducting coil using the same, and an MRI without lowering a critical current value and a critical current density of the MgB2 wire material to an extreme. To solve the problem, provided are a superconducting wire having a plurality of MgB2 strands and a first base metal, a superconducting coil using the same, and an MRI, the superconducting wire being characterized in that in a cross section orthogonal to a wire longitudinal direction, a center point of an area surrounded by the plurality of MgB2 strands and a center axis of a cross section of the superconducting wire are disposed in separated positions.

Quench protected structured (QPS) superconducting cables, methods of fabricating the same, and methods of bending the same are disclosed. The methods of bending the QPS superconducting cables can be employed to produce windings. The QPS superconducting cables can rapidly drive a distributed quench to a normal conducting state in a superconducting cable if a region of the cable spontaneously quenches during high current operation.