Operational characteristics of an extremely low resistance (ELR) film comprised of an ELR material may be improved by depositing a modifying material onto appropriate surfaces of the ELR film to create a modified ELR film. In some implementations of the invention, the ELR film may be in the form of a c-film. In some implementations of the invention, the ELR film may be in the form of an a-b film, an a-film or a b-film. The modified ELR film has improved operational characteristics over the ELR film alone or without the modifying material. Such operational characteristics may include operating in an ELR state at increased temperatures, carrying additional electrical charge, operating with improved magnetic properties, operating with improved mechanic properties or other improved operational characteristics. In some implementations of the invention, the ELR material is a mixed-valence copper-oxide perovskite, such as, but not limited to YBCO. In some implementations of the invention, the modifying material is a conductive material that bonds easily to oxygen, such as, but not limited to, chromium.

A bistable device allows supercurrent to flow when functioning in one regime, wherein magnetization directions of different magnetic layers are antiparallel, but restricts supercurrent when switched to function in a resistive regime, wherein the magnetization directions are parallel. In the first regime, the device acts as a Josephson junction, which allows it to be used in superconducting quantum interference devices (SQUIDs) and other circuits in which quantization of magnetic flux in a superconducting loop is desired. In the second, resistive regime, flux quantization is effectively eliminated in loops containing the device, and current is diverted to parallel superconducting components. The bistable device thereby acts as a superconducting switch, useful for a variety of circuit applications, including to steer current for memory or logic circuits, adjust logical circuit functionality at runtime, or to burn off stray flux during cooldown.

A system that includes: an array of qubits, each qubit of the array of qubits comprising a first electrode corresponding to a first node and a second electrode corresponding to a second node, wherein, for a first qubit in the array of qubits, the first qubit is positioned relative to a second qubit in the array of qubits such that a charge present on the first qubit induces a same charge on each of the first node of the second qubit and the second node of the second qubit, such that coupling between the first qubit and the second qubit is reduced, and wherein none of the nodes share a common ground is disclosed.

A physical vapor deposition system includes a chamber, three target supports to targets, a movable shield positioned having an opening therethrough, a workpiece support to hold a workpiece in the chamber, a gas supply to deliver nitrogen gas and an inert gas to the chamber, a power source, and a controller. The controller is configured to move the shield to position the opening adjacent each target in turn, and at each target cause the power source to apply power sufficient to ignite a plasma in the chamber to cause deposition of a buffer layer, a device layer of a first material that is a metal nitride suitable for use as a superconductor at temperatures above 8 K on the buffer layer, and a capping layer, respectively.

The present disclosure provides a method for using a group of actinide and lanthanide (rare earth) metal compounds as well as early transition metal compounds that have the electric superconducting property at 151 K or higher that have the potential to reach a superconducting transition (critical) temperature (Tc) of room temperature (298 K) or even higher.

Various techniques and apparatus permit fabrication of superconductive circuits. A niobium/aluminum oxide/niobium trilayer may be formed and individual Josephson Junctions (JJs) formed. A protective cap may protect a JJ during fabrication. A hybrid dielectric may be formed. A superconductive integrated circuit may be formed using a subtractive patterning and/or additive patterning. A superconducting metal layer may be deposited by electroplating and/or polished by chemical-mechanical planarization. The thickness of an inner layer dielectric may be controlled by a deposition process. A substrate may include a base of silicon and top layer including aluminum oxide. Depositing of superconducting metal layer may be stopped or paused to allow cooling before completion. Multiple layers may be aligned by patterning an alignment marker in a superconducting metal layer.

The present subject matter provides technical solutions for the technical problems facing quantum computing by improving the accuracy and precision of qubit readout. Technical solutions described herein improves the readout fidelity by reducing the ambiguity between the bright and dark states. In an embodiment, this includes transferring the qubit population that is in the dark quantum state to an auxiliary third state. The auxiliary third state remains dark and reduces the mixing between the logical bright and dark states. This process uses multiple laser pulses to ensure high fidelity population transfer, thus preserving the dark nature of the dark state. Improving readout fidelity of 171Yb+ qubits may improve fidelity by an order of magnitude, such as by improving readout fidelity from 99.9% to 99.99%. This improvement in detection fidelity may substantially increase the computational power of a quantum computer.

A bistable device allows supercurrent to flow when functioning in one regime, wherein magnetization directions of different magnetic layers are antiparallel, but restricts supercurrent when switched to function in a resistive regime, wherein the magnetization directions are parallel. In the first regime, the device acts as a Josephson junction, which allows it to be used in superconducting quantum interference devices (SQUIDs) and other circuits in which quantization of magnetic flux in a superconducting loop is desired. In the second, resistive regime, flux quantization is effectively eliminated in loops containing the device, and current is diverted to parallel superconducting components. The bistable device thereby acts as a superconducting switch, useful for a variety of circuit applications, including to steer current for memory or logic circuits, adjust logical circuit functionality at runtime, or to burn off stray flux during cooldown.

A device, system and method for measuring the temperature at the center of a normal hotspot and the heat escape time in superconducting filament or nanowire toward the substrate. The device includes structured layers; a superconducting filament is implemented as an active layer where an electrical current pulse or single photon radiation generates a hot spot; a sensitive semiconductor layer of germanium serves as a temperature sensor (thermometer); and a thin layer of insulating silicon oxide is intercalated between the superconducting layer and the germanium having a thickness in the range of 2-10 nm and width 5-100 m. This device provides a direct measurement of the temperature at the center of a hot spot and determination of the heat escape time toward a substrate; and can be used to determine the sensitivity of a superconducting single photon detector device to a next upcoming photon.

Various techniques and apparatus permit fabrication of superconductive circuits. A niobium/aluminum oxide/niobium trilayer may be formed and individual Josephson Junctions (JJs) formed. A protective cap may protect a JJ during fabrication. A hybrid dielectric may be formed. A superconductive integrated circuit may be formed using a subtractive patterning and/or additive patterning. A superconducting metal layer may be deposited by electroplating and/or polished by chemical-mechanical planarization. The thickness of an inner layer dielectric may be controlled by a deposition process. A substrate may include a base of silicon and top layer including aluminum oxide. Depositing of superconducting metal layer may be stopped or paused to allow cooling before completion. Multiple layers may be aligned by patterning an alignment marker in a superconducting metal layer.