The problem is to attain a joint for multi-core superconducting wires having a high critical current property. The joint for superconducting wires of the present invention has a first sintered body containing MgB.sub.2 configured to fix a plurality of superconducting wires, and a second sintered body containing MgB.sub.2 configured to joint the superconducting wires.

The problem is to attain a joint for multi-core superconducting wires having a high critical current property. The joint for superconducting wires of the present invention has a first sintered body containing MgB.sub.2 configured to fix a plurality of superconducting wires, and a second sintered body containing MgB.sub.2 configured to joint the superconducting wires.

A connection system for a quantum computer that employs constant impedance connectors with attenuation or filtering components or both embedded therein or within an adaptor removably insertable within an adaptor housing for use in a cryogenically cooled quantum computer. The connection system provides a higher density of cables traversing through a hermetic sealed top plate, and which are accessible to chill blocks to reduce the thermal energy from the signal lines. Attenuators or filter circuits are embedded in the constant impedance connector housings, or provided in adaptors that connect on each end to form mating constant impedance connections, in order to reduce signal strength as the signal progresses through the cryogenic environment and to remove extraneous electrical signal noise.

There is provided a technique for producing a superconducting wire material in which the yield in a process of joining superconducting wire materials is improved over the related art. A method for producing a superconducting wire material lengthened by joining end portions of superconducting wire materials each having an oxide superconducting film, the end portions serving as joining surfaces, includes a step of disposing a micro-crystal of an oxide superconducting material on each of the joining surfaces of the oxide superconducting films, a pasting step of overlapping and pasting together the joining surfaces on which the micro-crystal is disposed, and a heat joining step of heating the overlapped joining surfaces to grow the micro-crystal, thereby forming, as a joining layer, a superconducting layer of the oxide superconducting material to join the joining surfaces to each other. A superconducting joining member for lengthening a superconducting wire material by performing heating while the superconducting joining member is pasted so as to bridge oxide superconducting thin films of two superconducting wire materials to join the two superconducting wire materials, wherein a micro-crystal of an oxide superconducting material is disposed on a joining surface.

There is provided a technique for producing a superconducting wire material in which the yield in a process of joining superconducting wire materials is improved over the related art. A method for producing a superconducting wire material lengthened by joining end portions of superconducting wire materials each having an oxide superconducting film, the end portions serving as joining surfaces, includes a step of disposing a micro-crystal of an oxide superconducting material on each of the joining surfaces of the oxide superconducting films, a pasting step of overlapping and pasting together the joining surfaces on which the micro-crystal is disposed, and a heat joining step of heating the overlapped joining surfaces to grow the micro-crystal, thereby forming, as a joining layer, a superconducting layer of the oxide superconducting material to join the joining surfaces to each other. A superconducting joining member for lengthening a superconducting wire material by performing heating while the superconducting joining member is pasted so as to bridge oxide superconducting thin films of two superconducting wire materials to join the two superconducting wire materials, wherein a micro-crystal of an oxide superconducting material is disposed on a joining surface.

In a high-temperature superconducting (HTS) wire connection assembly in which HTS wires each including a HTS layer are connected to each other, a first HTS wire and a second HTS wire that face each other are connected to each other at a plurality of joint portions separated from each other along a longitudinal direction of the first HTS wire and the second HTS wire. Each of the plurality of joint portions may preferably have any one of a rectangle shape, a rounded rectangle shape, and an ellipse shape, and it is preferable to satisfy 0.1<L/W<1.5, and is more preferable to satisfy 0.25<L/W<0.75 when a length in the longitudinal direction of the HTS wire is taken as L and a length in a width direction of the HTS wire is taken as W. It is also preferable that W and/or L monotonously increase from upstream side toward downstream side along the longitudinal direction of the wire.

In a high-temperature superconducting (HTS) wire connection assembly in which HTS wires each including a HTS layer are connected to each other, a first HTS wire and a second HTS wire that face each other are connected to each other at a plurality of joint portions separated from each other along a longitudinal direction of the first HTS wire and the second HTS wire. Each of the plurality of joint portions may preferably have any one of a rectangle shape, a rounded rectangle shape, and an ellipse shape, and it is preferable to satisfy 0.1<L/W<1.5, and is more preferable to satisfy 0.25<L/W<0.75 when a length in the longitudinal direction of the HTS wire is taken as L and a length in a width direction of the HTS wire is taken as W. It is also preferable that W and/or L monotonously increase from upstream side toward downstream side along the longitudinal direction of the wire.

According to a first aspect of the present invention, there is provided a method of forming a superconducting joint between ReBCO tapes. Two or more ReBCO tapes are provided, each having an exposed ReBCO region. A bridge is provided, comprising an exposed ReBCO layer and an oxygen-permeable backing on the exposed ReBCO layer. Each exposed ReBCO region is bonded to the exposed ReBCO layer of the bridge by heating to a first temperature (T1) in an environment where the partial pressure of oxygen is sufficiently low that the melting point of the ReBCO (T.sub.R) is less than the melting point of silver (T.sub.Ag), the temperature (T1) being between the melting point of the ReBCO (T.sub.R) and the melting point of silver (T.sub.Ag), (T.sub.R<T1<T.sub.Ag). The resulting joint is annealed at a second temperature (T2) which is less than the melting point of ReBCO (T.sub.R) (T2<T.sub.R), for a time (t), in an environment where the partial pressure of oxygen is sufficient to reoxygenate the ReBCO at the second temperature (T2).

According to a first aspect of the present invention, there is provided a method of forming a superconducting joint between ReBCO tapes. Two or more ReBCO tapes are provided, each having an exposed ReBCO region. A bridge is provided, comprising an exposed ReBCO layer and an oxygen-permeable backing on the exposed ReBCO layer. Each exposed ReBCO region is bonded to the exposed ReBCO layer of the bridge by heating to a first temperature (T1) in an environment where the partial pressure of oxygen is sufficiently low that the melting point of the ReBCO (T.sub.R) is less than the melting point of silver (T.sub.Ag), the temperature (T1) being between the melting point of the ReBCO (T.sub.R) and the melting point of silver (T.sub.Ag), (T.sub.R<T1<T.sub.Ag). The resulting joint is annealed at a second temperature (T2) which is less than the melting point of ReBCO (T.sub.R) (T2<T.sub.R), for a time (t), in an environment where the partial pressure of oxygen is sufficient to reoxygenate the ReBCO at the second temperature (T2).

The various embodiments described herein include methods, devices, and systems for fabricating and operating superconducting circuits. In one aspect, an electric circuit includes: (1) a first superconducting component having a first terminal, a second terminal, and a constriction region between the first terminal and the second terminal; (2) a second superconducting component having a third terminal and a fourth terminal; and (3) a first electrically-insulating component that thermally couples the first superconducting component and the second superconducting component such that heat produced at the constriction region is transferred through the first component to the second superconducting component.