Japan Science and Technology Agency

Nec Corporation

Other

Tohoku University

Riken Corporation

Yasunobu Nakamura

Akihiro Kirihara

Jaw-Shen Tsai

Shinichi Yorozu

Shuhei Tamate

Yutaka Tabuchi

Atsushi Noguchi

Tsuyoshi Yamamoto

Hiroyuki Endoh

Eiji Saitoh

Kenichi Uchida

Junichi Sone

Kazuki Koshino

Takanari Yasui

Alto Osada

Youichi Ohtsuka

Shingo Kono

A quantum gate device includes a first superconducting circuit which includes at least one of Josephson devices in an annular circuit including a superconducting wire and resonates at a first resonance frequency, a second superconducting circuit which includes at least one of Josephson devices in an annular circuit including a superconducting wire and resonates at a second resonance frequency, a connection unit which includes a capacitor and a superconducting wire provided at each electrode of the capacitor and connects the first and second circuits, a magnetic field application means applying a magnetic field to one or both of the first and second circuits, a quantum gate control electromagnetic wave irradiation unit irradiating one of the first and second circuits with a control electromagnetic wave, and an unnecessary transition suppression electromagnetic wave irradiation unit irradiating one of the first and second circuits with an unnecessary interaction suppression electromagnetic wave.

Quantum gate device

This nonlinear microwave filter is provided with quantum bits that are formed on a circuit board in which target quantum bits are formed which are quantum bits controlled in a superconducting quantum circuit, and that are coupled to a control waveguide to which the target quantum bits are coupled, wherein the distance to a waveguide end in the control waveguide is within a predetermined range from semi integer times the resonant wavelength, the quantum bits have a resonant frequency in which the difference from the resonant frequency of the target quantum bits is within a predetermined range, and the coupling to the control waveguide is stronger by a predetermined value than the coupling between the target quantum bits and the control waveguide.

Nonlinear microwave filter

A microwave photon control device includes a first qubit and a second qubit that are connected in parallel to a waveguide through which microwave photons propagate, and a direct coupling between the first qubit and the second qubit. An interval between the first qubit and the second qubit is (¼+n/2) times as long as a wavelength of microwave photons (where n is an integer equal to or larger than 0). A quantum entangled state is formed between the first qubit and the second qubit. The direct coupling cancels out a coupling via the waveguide between the first qubit and the second qubit. By a relaxation rate of the first qubit and the second qubit, and a phase of the quantum entangled state being controlled, the microwave photon control device operates while switching between a first operation mode, a second operation mode, and a third operation mode.

Microwave photon control device, microwave photon transmitter, microwave photon receiver, microwave photon repeater, and quantum computer

A superconducting complex quantum computing circuit includes a circuit substrate in which a wiring pattern of a circuit element including quantum bits and measurement electrodes, and ground patterns are formed, and through-electrodes connecting the ground pattern formed on a first surface of the substrate surface and the ground pattern formed on a second surface; a first ground electrode including a first contact portion in contact with the ground patterns, and a first non-contact portion having a shape corresponding to a shape of the wiring pattern; a second ground electrode including a second contact portion in contact with the ground pattern; a control signal line provided with a contact spring pin at a tip; and a pressing member that presses the first ground electrode against the first surface of the circuit substrate or presses the second ground electrode against the second surface of the circuit substrate.

Superconducting complex quantum computing circuit

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.

An object of the present invention is to provide a low-cost thermoelectric converter element having high productivity and excellent conversion efficiency. A thermoelectric converter element according to the present invention includes a substrate, a magnetic filmprovided on the substratewith a certain magnetization direction A and formed of a polycrystalline magnetically insulating material, and an electrodeprovided on the magnetic filmwith a material exhibiting a spin-orbit interaction. When a temperature gradient is applied to the magnetic film, a spin current is generated so as to flow from the magnetic filmtoward the electrode. A current I is generated in a direction perpendicular to the magnetization direction A of the magnetic filmby the inverse spin Hall effect in the electrode

Thermoelectric converter element, method of manufacturing thermoelectric converter element, and thermoelectric conversion method

A position detection device includes a thermoelectric conversion portion which includes a magnetic layer and a plurality of electrodes. The magnetic layer has magnetization. The plurality of electrodes are formed of a material having spin-orbit interaction, and are formed on the magnetic layer so as to extend in a direction which intersects with the magnetization direction of the magnetic layer. When an arbitrary location on the layer-surface of the magnetic layer is heated, the thermoelectric conversion portion modulates the effective temperature in the magnetic layer and induces a spin Seebeck effect. As a result, the thermoelectric conversion portion generates, from the plurality of electrodes, a voltage corresponding to the heated position as position information.

Position detection device

A thermoelectric conversion device includes: a substrate; two magnetic layers having a fixed magnetization direction with respect to the substrate; and at least one electrode including a material having a spin orbit interaction, wherein a gap (or dielectric layer of low thermal conductivity) is provided between the magnetic layers. A thickness of the gap (or dielectric layer) is of a distance within the range at that a magnetic dipole interaction is exerted, and a film thickness of the magnetic layers is of about a characteristic length determined by diffusion or the like of a magnetic excitation.

Thermoelectric conversion device

A control quantum bit circuit and a target quantum bit circuit each have a quantum box electrode including a superconductor, a counter electrode coupled to the quantum box electrode through a tunnel barrier, and a gate electrode coupled to the quantum box electrode through a gate capacitor. The quantum box electrode of the control quantum bit circuit is coupled to the quantum box electrode of the target quantum bit circuit through a box-electrode coupling capacitor.

Coupled superconducting charge quantum bit device and controlled-not gate using the same

High device reliability, a reduction in power consumption, and a high operation speed are achieved. When a predetermined bias voltage is applied between a source and a drain to change a gate voltage, a current discretely flows between the source and the drain in accordance with quantized electrostatic energy levels in an island electrode . The switching ON/OFF of the current between the source and the drain in this case is enabled by applying &frac12;-electron charge to a gate. When the gate voltage induces polarization in a ferroelectric layer , its electric field is applied to the island electrode . The current between the source and the drain in this case can be measured with high sensitivity. Charge holding is carried out by the polarization in the ferroelectric layer , and stored data can be held even if power supply is cut off.

Growing community of inventors

Tokyo, Japan

Yasunobu Nakamura