A reversible memory element is provided. The reversible memory element comprises a reversible memory cell comprising a Josephson junction and a passive inductor. A ballistic interconnect is connected to the reversible memory cell by a bidirectional input/output port. A polarized input fluxon propagating along the ballistic interconnect exchanges polarity with a stationary stored fluxon in the reversible memory cell in response to the input fluxon reflecting off the reversible memory cell.

An apparatus includes a substrate, a classical computing processor formed on the substrate, a quantum computing processor formed on the substrate, and one or more coupling components between the classical computing processor and the quantum computing processor, the one or more coupling components being formed on the substrate and being configured to allow data exchange between the classical computing processor and the quantum computing processor.

A quantum gate device includes a first superconducting circuit which resonates at a first resonance frequency, second superconducting circuit which resonates at a second resonance frequency, and connector which connects these circuits. The first superconducting circuit includes a single first Josephson device, second Josephson device group, and first capacitor. The second Josephson device group includes n Josephson devices connected by a line made of a superconductor. The Josephson energy possessed by each of the n Josephson devices is greater than n times that of the first Josephson device. The quantum gate device further includes a magnetic field applier which applies a static magnetic field to the partial superconducting circuit, and an electromagnetic wave irradiator (first electromagnetic wave irradiator) which irradiates the first superconducting circuit and/or second superconducting circuit with an electromagnetic wave having a difference frequency which is equal to the difference between the first and second resonance frequencies.

Novel and useful quantum structures having a continuous well with control gates that control a local depletion region to form quantum dots. Local depleted well tunneling is used to control quantum operations to implement quantum computing circuits. Qubits are realized by modulating gate potential to control tunneling through local depleted region between two or more sections of the well. Complex structures with a higher number of qdots per continuous well and a larger number of wells are fabricated. Both planar and 3D FinFET semiconductor processes are used to build well to gate and well to well tunneling quantum structures. Combining a number of elementary quantum structure, a quantum computing machine is realized. An interface device provides an interface between classic circuitry and quantum circuitry by permitting tunneling of a single quantum particle from the classic side to the quantum side of the device. Detection interface devices detect the presence or absence of a particle destructively or nondestructively.

It is an objective to provide an arrangement for reducing qubit leakage errors in a quantum computing system. According to an embodiment, an arrangement for reducing qubit leakage errors includes a first qubit and a second qubit selectively couplable to each other. The arrangement also includes an energy dissipation structure that is selectively couplable to the first qubit. The energy dissipation structure is configured to dissipate energy transferred from the first qubit. The arrangement further includes a control unit configured to perform a first quantum operation to transfer a property of a quantum state from the first qubit to the second qubit, couple the first qubit to the energy dissipation structure for a time interval, and perform a second quantum operation to transfer the property of the quantum state from the second qubit to the first qubit after the time interval.

A multi-mode resonator is provided. The multi-mode resonator includes a housing and a cavity disposed in the housing, wherein the cavity includes a main cavity and a plurality of first subcavities disposed on a first lateral side of the main cavity.

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.

A semiconductor device of an embodiment includes a layered substance formed by laminating two-dimensional substances in two or more layers. The layered substance includes at least either one of a p-type region having a first intercalation substance between layers of the layered substance and an n-type region having a second intercalation substance between layers of the layered substance. The layered substance includes a conductive region that is adjacent to at least either one of the p-type region and the n-type region. The conductive region includes neither the first intercalation substance nor the second intercalation substance. A sealing member is formed on the conductive region, or on the conductive region and an end of the layered substance.

Method and circuit for reading a value {circumflex over (σ)}.sub.z stored in a quantum information unit (qubit) memory having a qubit frequency ω.sub.a, with a resonator defined by a resonator damping rate κ, a resonator frequency ω.sub.r, a resonator electromagnetic field characterized by â.sup.† and â, a longitudinal coupling strength g.sub.z, an output â.sub.out and a longitudinal coupling g.sub.z{circumflex over (σ)}.sub.z(â.sup.†+â). At a quantum non-demolition (QND) longitudinal modulator, periodically modulating the longitudinal coupling strength g.sub.z with a signal of amplitude {tilde over (g)}.sub.z at least three (3) times greater than the resonator damping rate κ and of frequency ω.sub.m with ω.sub.m+κ resonant with ω.sub.r, wherein the longitudinal coupling strength g.sub.z varies over time (t) in accordance with g.sub.z(t)=g.sub.z+{tilde over (g)}.sub.z cos(ω.sub.mt) with g.sub.z representing an average value of g.sub.z and at a QND homodyne detector, measuring the value {circumflex over (σ)}.sub.z of the qubit memory from a phase reading of the output {circumflex over (σ)}.sub.out.

This disclosure describes a superconducting device comprising a trench and a cavity that extends through a superconducting base layer. The trench crosses the cavity. The superconducting device further comprises a first junction layer that extends from a first region of the superconducting base layer to the cavity, an insulating layer on the surface of the first junction layer, and a second junction layer that extends from a second region of the superconducting base layer to the cavity. The second junction layer overlaps with the insulating layer on the bottom of the cavity. The disclosure also describes a method for producing this disclosed superconducting device.