A hybrid heterostructure includes a semiconductor layer comprising indium antimonide, a superconductor layer comprising aluminum, and a screening layer between the semiconductor layer and the superconductor layer, the screening layer comprising indium arsenide. By including a screening layer of indium arsenide between the semiconductor layer of indium antimonide and the superconductor layer of aluminum, a high-performance and durable hybrid heterostructure suitable for use in quantum computing devices is provided.

A quantum bit circuit includes a first Majorana carrier that includes a first edge and extends in a first direction and a second Majorana carrier that includes a second edge and extends in a second direction intersecting with the first direction, in which the first Majorana carrier includes a first region where a Majorana particle can exist, in a portion of the first edge overlapping the second edge in plan view, the second Majorana carrier includes a second region where a Majorana particle can exist, in a portion of the second edge overlapping the first edge in plan view, and the Majorana particle in the first region and the Majorana particle in the second region are exchangeable.

A superconducting connecting system includes an anti-fuse structure. There is a first superconducting trace having a first segment that is cantilevered over a cavity a substrate. A second superconducting trace having a second segment is cantilevered over the cavity in the substrate. A first auxiliary segment is coupled to the first segment and suspended over the cavity. A second auxiliary segment is coupled to the second segment and suspended over the cavity. The first segment and the second segment face each other and have a predetermined gap therebetween. The first segment and the second segment are configured to receive an output of a laser. An amount of material of the first and second auxiliary segment is based on creating a fuse ball joint that provides an electrical short between the first superconducting trace and the second superconducting trace, upon receiving the output of the laser.

A superconducting connecting system includes an anti-fuse structure. There is a first superconducting trace having a first segment that is cantilevered over a cavity a substrate. A second superconducting trace having a second segment is cantilevered over the cavity in the substrate. A first auxiliary segment is coupled to the first segment and suspended over the cavity. A second auxiliary segment is coupled to the second segment and suspended over the cavity. The first segment and the second segment face each other and have a predetermined gap therebetween. The first segment and the second segment are configured to receive an output of a laser. An amount of material of the first and second auxiliary segment is based on creating a fuse ball joint that provides an electrical short between the first superconducting trace and the second superconducting trace, upon receiving the output of the laser.

Materials and methods are disclosed for fabricating superconducting integrated circuits for quantum computing at millikelvin temperatures, comprising both quantum circuits and classical control circuits, which may be located on the same integrated circuit or on different chips of a multi-chip module. The materials may include components that reduce defect densities and increase quantum coherence times. Multilayer fabrication techniques provide low-power and a path to large scale computing systems. An integrated circuit system for quantum computing is provided, comprising: a substrate; a kinetic inductance layer having a kinetic inductance of at least 5 pH/square; a plurality of stacked planarized superconducting layers and intervening insulating layers, formed into a plurality of Josephson junctions having a critical current of less than 100 μA/μm.sup.2; and a resistive layer that remains non-superconducting at a temperature below 1 K, configured to damp the plurality of Josephson junctions.

A method for adjusting a resonance frequency of a qubit in a quantum mechanical device includes providing a substrate having a frontside and a backside, the frontside having at least one qubit formed thereon, the at least one qubit comprising capacitor pads; and removing substrate material from the backside of the substrate at an area opposite the at least one qubit to alter a capacitance around the at least one qubit so as to adjust a resonance frequency of the at least one qubit.

A fusion reactor includes a fusion plasma reactor chamber. A magnetic coil structure is disposed inside of the fusion plasma reactor chamber, and a structural component is also disposed inside of the fusion plasma reactor chamber. The structural component couples the magnetic coil structure to the fusion plasma reactor chamber. A superconducting material is disposed at least partially within the structural component. A plurality of cooling channels are disposed at least partially within the structural component. An insulating material is disposed at least partially within the structural component.

Provided is a connection body of high-temperature superconducting wire materials including a first oxide high-temperature superconducting wire material and a second oxide high-temperature superconducting wire material, characterized in that a first superconducting layer of the first oxide high-temperature superconducting wire material and a second superconducting layer of the second oxide high-temperature superconducting wire material are bonded together via a junction including M-Cu—O (wherein M is a single metal element or a plurality of metal elements included in the first superconducting layer or the second superconducting layer). The connection body may be, for example, a connection body of Bi2223 wire materials, and the junction may include CaCuO.sub.2.

A superconducting integrated circuit has a first superconducting device with a first superconducting loop, where the first superconducting loop has a first superconducting trace in a first layer of the superconducting integrated circuit, and a second superconducting device with a second superconducting loop, where the second superconducting loop has a second superconducting trace in a second layer. The first superconducting loop crosses the second superconducting loop in a crossing region. At least a portion of each of the first and the second superconducting trace inside the crossing region is narrower than at least a portion of each of the traces outside the crossing region, and follows a respective circuitous path which is inductively proximate to at least a portion of the other path.

A quantum processing unit is disclosed. The quantum processing unit includes at least one superconducting qubit that is based on phase-biased linear and non-linear inductive-energy elements. A superconducting phase difference across the linear and non-linear inductive-energy elements is biased, for example, by an external magnetic field, such that quadratic potential energy terms of the linear and non-linear inductive-energy elements are cancelled at least partly. In a preferred embodiment, such cancellation is at least 30%. The partial cancellation of the quadratic potential energy terms makes it possible to implement a high-coherence high-anharmonicity superconducting qubit design.