A T-joint connector can be useful for connecting one or more flex circuit boards to quantum hardware including one or more qubits. The T-joint connector can include one or more flex circuit boards. Each of the one or more flex circuit boards can include one or more signal lines and one or more spring interconnects including a superconducting material. The one or more spring interconnects can be coupled to the one or more signal lines. The one or more spring interconnects can be configured to couple the one or more signal lines to one or more signal pads disposed on a mounting circuit board associated with the quantum hardware. The superconducting material can be superconducting at a temperature less than about 3 kelvin.

A flex circuit board can be used in transmitting signals in a quantum computing system. The flex circuit board can include at least one dielectric layer and at least one superconducting layer disposed on a surface of the at least one dielectric layer. The at least one superconducting layer can include a superconducting material. The superconducting material can be superconducting at a temperature less than about 3 kelvin. The flex circuit board can have at least one metal structure electroplated onto the at least one superconducting layer.

According to an embodiment, a superconducting wire includes a substrate, an intermediate layer formed on the substrate, a superconducting layer formed on the intermediate layer, and a protective layer formed on the superconducting layer. The superconducting layer has a first portion, a second portion, and a third portion between the first portion and the second portion in the longitudinal direction of the superconducting wire. The protective layer on the third portion is at least partially removed.

A method of manufacturing superconductor structures includes depositing a release film on a substrate, forming a stack of films comprising an elastic material and a superconductor film, releasing a portion of the elastic material by selective removal of the release film so that portion lifts out of the substrate plane to form elastic springs. A method of manufacturing superconductor structures includes depositing a release film on a substrate, forming a stack of films comprising at least an elastic material, releasing a portion of the elastic material so that portion lifts out of a plane of the substrate to form elastic springs, and coating the elastic springs with a superconductor film.

A strip conductor device includes first and second elongated strip conductor elements, each configured to be coupled at a coupling-in end to a contact device for coupling-in electric current and at a coupling-out end to a contact device for coupling-out electric current. The first elongated strip conductor element is a first strip conductor that has a substrate layer that carries a conductor layer that has barrier elements along a length of the conductor layer. The second elongated strip conductor element is a second strip conductor that has a substrate layer that carries a conductor layer that has barrier elements along a length of the conductor layer. The first strip conductor element forms a layer arrangement with the second strip conductor element and the coupling-in ends and the coupling-out ends of the first and second strip conductor elements lie one above the other.

The present invention relates to a quantum computing unit comprising a superconducting substrate or other superconducting component, at least three outer Majorana modes, and at least one inner Majorana mode, wherein the at least three outer Majorana modes are located along an outer perimeter, and wherein the at least one inner Majorana mode is located within the outer perimeter. This spatial configuration of the four participating Majorana modes allows to control the time-dependent coupling between the respective Majorana modes. The related quantum gates can be performed perfectly in a finite time, preferably with a frequency of up to several GHz. These include the braiding gate, the π/8 magic phase gate, the π/12 phase gate, and, for multi-qubit systems, the CNOT gate. The robustness of the mechanism guarantees that for special times the quantum gate is conducted the quantum gate is perfectly realized. This property is independent of material specific parameters. Hence, the behavior can be expected in all systems where Majorana zero modes appear in the center of Abrikosov vortices, in particular, not only in FeTeSe, which we consider as an example.

According to an example aspect of the present invention, there is provided an apparatus comprising: an optic fibre input (31); a plurality of photonic detectors (34) comprising a nanowire and biased with an electric input; a set of modulators (35) connected to the optic fibre input (31), each of the modulators (35) being connected to one of the photonic detectors (34) for forming a modulated optical detector signal; and an optic fibre output (40) for the modulated optical detector signal. The optic fibre input (31), the photonic detectors (34), the set of modulators (35), and the optic fibre output (40) are formed on a single chip (1).

A structure has a substrate, and a spring structure disposed on the substrate, the spring structure having an anchor portion disposed on the substrate, an elastic material having an intrinsic stress profile that biases a region of the elastic material to curl away from the substrate, and a superconductor film in electrical contact with a portion of the elastic material. A method of manufacturing superconductor structures includes depositing a release film on a substrate, forming a stack of films comprising an elastic material and a superconductor film, releasing a portion of the elastic material by selective removal of the release film so that portion lifts out of the substrate plane to form elastic springs. A method of manufacturing superconductor structures includes depositing a release film on a substrate, forming a stack of films comprising at least an elastic material, releasing a portion of the elastic material so that portion lifts out of a plane of the substrate to form elastic springs, and coating the elastic springs with a superconductor film.

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

A system and method for fabricating accelerator cavities comprises forming at least two half cavities and joining the half cavities with a longitudinal seal. The half cavities can comprise at least one of aluminum, copper, tin, and copper alloys. The half cavities can be coated with a superconductor or combination of materials configured to form a superconductor coating.