In-situ patterning of semiconductor structures is performed using one or more shadow walls in conjunction with an angled deposition beam. A shadow wall protrudes outwardly from the surface of a substrate to define an adjacent shadow region in which deposition is prevented due to the shadow wall inhibiting the passage of the angled deposition beam. Hence, deposition will not occur on a surface portion of a semiconductor structure within the shadow region. Shadow walls can thus be used to achieve selective patterning of semiconductor structures. The shadow walls themselves are formed of semiconductor. In one implementation, the semiconductor structure and the one or more shadow walls used to selectively pattern it may be formed using selective area growth (SAG).

Approaches useful to operation of scalable processors with ever larger numbers of logic devices (e.g., qubits) advantageously take advantage of QFPs, for example to implement shift registers, multiplexers (i.e., MUXs), de-multiplexers (i.e., DEMUXs), and permanent magnetic memories (i.e., PMMs), and the like, and/or employ XY or XYZ addressing schemes, and/or employ control lines that extend in a braided pattern across an array of devices. Many of these described approaches are particularly suited for implementing input to and/or output from such processors. Superconducting quantum processors comprising superconducting digital-analog converters (DACs) are provided. The DACs may use kinetic inductance to store energy via thin-film superconducting materials and/or series of Josephson junctions, and may use single-loop or multi-loop designs. Particular constructions of energy storage elements are disclosed, including meandering structures. Galvanic connections between DACs and/or with target devices are disclosed, as well as inductive connections.

Provided are a photon detection device and a photon detection method being practical, capable of performing photon detection in which no afterpulse is generated and generation of a dark count is suppressed, and capable of obtaining a high counting rate with low jitter. The photon detection device of the present invention includes: a photon detection section having a long plate-shaped superconducting stripline whose plate surface is a photon detection surface, and a bias current supply section supplying a bias current to the superconducting stripline; and a single flux quantum comparator circuit capable of detecting magnetic flux scattered from the superconducting stripline upon photon detection.

Quantum devices with two-sided or single-sided dual-purpose Majorana zero mode (MZM) junctions are described. An example quantum device comprises at least one superconducting island configurable to support at least one pair of Majorana zero modes (MZMs). The quantum device further includes a first conductor configurable to be coupled with at least one MZM of the at least one pair of MZMs, where the first conductor is configurable to be in at least one of a grounded state or a Coulomb blockade state. The quantum device further includes a second conductor configurable to be coupled with the at least one MZM of the at least one pair of MZMs, where the second conductor is configurable to be in at least one of a grounded state or a Coulomb blockade state.

Quantum devices formed from a single superconducting wire having a configurable ground connection are described. An example quantum device, configurable to be grounded, comprises a single superconducting wire having at least a first section and a second section, each of which is configurable to be in a topological phase and at least a third section configurable to be in a trivial phase. The quantum device further comprises semiconducting regions formed adjacent to the single superconducting wire, where the single superconducting wire is configurable to store quantum information in at least four Majorana zero modes (MZMs). The semiconducting regions formed adjacent to the single superconducting wire may be used to measure quantum information stored in the at least four MZMs.

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for constructing and programming quantum hardware for quantum annealing processes.

The invention relates to a component for electric, magnetic, or optical applications, comprising at least two adjacent layers (G.sub.B1, G.sub.B2) with a common boundary region (G.sub.FB). The first layer has graphite with a Bernal crystal structure (graphite 2H), and the second layer has graphite with a rhombohedral crystal structure (graphite 3R). The boundary region has at least one boundary area (G.sub.G) which has superconductive properties at a transition temperature (T.sub.c) higher than 78 K and/or a critical magnetic flux density (B.sub.k) greater than 1 T.

A method for performing quantum annealing computation for solving a discrete optimization problem includes the steps of: (a) identifying an operation for transferring an energy state of one of two physical systems (u, d) having the same quantum state to a low energy state and transferring an energy state of the other of the two physical systems to a high energy state; (b) constructing a network structure among a plurality of physical systems that indicates an order of application of the operation of the step (a) on two physical systems among the plurality of physical systems; and (c) obtaining a physical system having a minimum energy state in the plurality of physical systems by applying the operation of the step (a) to the plurality of physical systems according to the order indicated in the network structure of step (b).

Various fabrication method are disclosed. In one such method, at least one structure is formed on a substrate which protrudes outwardly from a plane of the substrate. A beam is used to form a layer of material, at least part of which is in direct contact with a semiconductor structure on the substrate, the semiconductor structure comprising at least one nanowire. The beam has a non-zero angle of incidence relative to the normal of the plane of the substrate such that the beam is incident on one side of the protruding structure, thereby preventing a portion of the nanowire in a shadow region adjacent the other side of the protruding structure in the plane of the substrate from being covered with the material.

The disclosure relates to a quantum device and method of fabricating the same. The device comprises one or more semiconductor-superconductor nanowires, each comprising a length of semiconductor material and a coating of superconductor material coated on the semiconductor material. The nanowires may be formed over a substrate. In a first aspect at least some of the nanowires are full-shell nanowires with superconductor material being coated around a full perimeter of the semiconductor material along some or all of the length of the wire, wherein the device is operable to induce at least one Majorana zero mode, MZM, in one or more active ones of the full-shell nanowires. In a second aspect at least some of the nanowires are arranged vertically relative to the plane of the substrate in the finished device.