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.

Electrical, mechanical, computing, and/or other devices that include components formed of extremely low resistance (ELR) materials, including, but not limited to, modified ELR materials, layered ELR materials, and new ELR materials, are described.

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).

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 device for guiding charge carriers and uses of the device are proposed, wherein the charge carriers are guided by means of a magnetic field along a curved or angled main path in a two-dimensional electron gas or in a thin superconducting layer, so that a different presence density is produced at electrical connections.

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.

This disclosure describes systems, methods, and apparatus for multilayer superconducting structures comprising electroplated Rhenium, where the Rhenium operates in a superconducting regime at or above 4.2 K, or above 1.8 K where specific temperatures and times of annealing have occurred. The structure can include at least a first conductive layer applied to a substrate, where the Rhenium layer is electroplated to the first layer. A third layer formed from the same or a different conductor as the first layer can be formed atop the Rhenium layer.

Proposed is a novel embedded structure for suppressing a disturbance in the cross sectional shape and a non-uniform deformation of a metal member arising in a precursor when producing an MgB2 multi-core wire material by a surface reduction process. This superconductive multi-core wire material precursor is characterized by having: soft Cu and Fe pure metals disposed in the center; mixed powder elements, each comprising as a sheath material a metal such as Fe or Nb having a barrier effect preventing a reaction between Mg and Cu, the mixed powder elements being disposed in a form that surrounds the periphery of the soft metal serving as the central material; and disposed around these, an outer shell layer produced from a harder metal than the central material and the sheath material.

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