The various embodiments described herein include methods, devices, and systems for operating superconducting circuitry. In one aspect, a superconducting component includes: (1) a superconductor having a plurality of alternating narrow and wide portions, each wide portion having a corresponding terminal; and (2) a plurality of heat sources, each heat source thermally coupled to a corresponding narrow portion such that heat from the heat source is transmitted to the corresponding narrow portion; where the plurality of heat sources is electrically isolated from the superconductor.

In some embodiments, a method and apparatus, as well as an article, may operate to determine downhole properties based on detected optical signals. An optical detection apparatus can include an optical detector including a superconducting nanowire single photon detector (SNSPD) for detecting light received at an input section of fiber optic cable. The optical detection apparatus can further include a cryogenic cooler configured to maintain the temperature of a light-sensitive region of the SNSPD within a superconducting temperature range of the SNSPD. Downhole properties are measured based on detected optical signals received at the optical detection apparatus. Additional apparatus, systems, and methods are disclosed.

Embodiments of a Majorana-based qubit are disclosed herein. The qubit is based on the formation of superconducting islands, some parts of which are topological (T) and some parts of which are non-topological. Also disclosed are example techniques for fabricating such qubits. In one embodiment, a semiconductor nanowire is grown, the semiconductor nanowire having a surface with an oxide layer. A dielectric insulator layer is deposited onto a portion of the oxide layer of the semiconductor nanowire, the portion being designed to operate as a non-topological segment in the quantum device. An etching process is performed on the oxide layer of the semiconductor nanowire that removes the oxide layer at the surface of the semiconductor nanowire but maintains the oxide layer in the portion having the deposited dielectric insulator layer. A superconductive layer is deposited on the surface of the semiconductor nanowire, including over the dielectric insulator layer.

Test structures and methods for superconducting bump bond electrical characterization are used to verify the superconductivity of bump bonds that electrically connect two superconducting integrated circuit chips fabricated using a flip-chip process, and can also ascertain the self-inductance of bump bond(s) between chips. The structures and methods leverage a behavioral property of superconducting DC SQUIDs to modulate a critical current upon injection of magnetic flux in the SQUID loop, which behavior is not present when the SQUID is not superconducting, by including bump bond(s) within the loop, which loop is split among chips. The sensitivity of the bump bond superconductivity verification is therefore effectively perfect, independent of any multi-milliohm noise floor that may exist in measurement equipment.

The various embodiments described herein include methods, devices, and systems for operating superconducting circuits. In one aspect, an electric circuit includes: (1) a superconductor component having a first terminal at a first end and a second terminal at a second end; (2) a gate component thermally-coupled to the superconductor component at a first location between the first terminal and the second terminal, where the gate component is thermally-coupled via a first section of the gate component; and where the gate component has a smallest width at the first section so as to focus resistive heating toward the superconductor component.

The present disclosure provides a method for making a single photon detector with a modified superconducting nanowire. The method includes: preparing a substrate; modifying a superconducting nanowire with stress on a surface of the substrate; and fabricating a superconducting nanowire single photon detector based on the superconducting nanowire with stress. Based on the above technical solution, in the superconducting nanowire single photon detector provided by the present disclosure, the device material layer film has a certain thickness, the critical temperature of the device material can be reduced, the uniformity of the device material and small superconducting transition width are ensured, thereby improving the detection efficiency of the device.

The various embodiments described herein include methods, devices, and systems for fabricating and operating superconducting photon detectors. In one aspect, a photon detector includes: (1) a first waveguide configured to guide photons from a photon source; (2) a second waveguide that is distinct and separate from the first waveguide and optically-coupled to the first waveguide; and (3) a superconducting component positioned adjacent to the second waveguide and configured to detect photons within the second waveguide.

A quantum computing device is fabricated by forming, on a superconductor layer, a first resist pattern defining a device region and a sensing region within the device region. The superconductor layer within the sensing region is removed, exposing a region of an underlying semiconductor layer outside the device region. The exposed region of the semiconductor layer is implanted, forming an isolation region surrounding the device region. Using an etching process subsequent to the implanting, the sensing region and a portion of the device region of the superconductor layer adjacent to the isolation region are exposed. By depositing a first metal layer within the sensing region, a tunnel junction gate is formed. A sensing region gate is formed by coupling the semiconductor layer with a second metal layer. A nanorod contact using the second metal within the portion of the device region outside the sensing region is formed.

A quantum computing device is fabricated by forming, on a superconductor layer, a first resist pattern defining a device region and a sensing region within the device region. The superconductor layer within the sensing region is removed, exposing a region of a first surface of an underlying semiconductor layer outside the device region. The exposed region of the semiconductor layer is implanted, forming an isolation region surrounding the device region. The sensing region and a portion of the device region of the superconductor layer are exposed. A sensing region contact is formed by coupling the first surface of the semiconductor layer with a first metal layer. A nanorod contact using the first metal within the portion of the device region outside the sensing region is formed. By depositing a second metal layer on a second surface of the semiconductor layer within the sensing region, a tunnel junction gate is formed.

Devices, systems, methods, computer-implemented methods, apparatus, and/or computer program products that can facilitate a suspended Majorana fermion device comprising an ion implant defined nanorod in a semiconducting device are provided. According to an embodiment, a quantum computing device can comprise a Majorana fermion device coupled to an ion implanted region. The quantum computing device can further comprise an encapsulation film coupled to the ion implanted region and a substrate layer. The encapsulation film suspends the Majorana fermion device in the quantum computing device.