US 12,597,932 B2Granted

Qubit control circuit

AssigneeNational University Corporation Yokohama National University

InventorsNaoki Takeuchi, Nobuyuki Yoshikawa

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Abstract

This qubit control circuit includes a first power supply line through which a first excitation current is input, a second power supply line through which a second excitation current is input, a first input signal line through which a first input signal is input, a first pulse train generation circuit that outputs a first pulse train having a repetition frequency corresponding to a frequency of the first excitation current generated by a first Josephson junction on the basis of a frequency of the first excitation current, a waveform of the second excitation current, and a logical state indicated by the first input signal, a second pulse train generation circuit that outputs a second pulse train having a repetition frequency corresponding to the frequency of the first excitation current generated by a second Josephson junction on the basis of the frequency of the first excitation current, and an output pulse train generation circuit that includes a third Josephson junction and outputs an output pulse train in which a waveform of the first pulse train is shaped by a repetition frequency of the second pulse train.

Claims5

Dependent claims

A qubit control circuit comprising:

a first power supply line through which a first excitation current, which is a current having a predetermined frequency, is input;
a second power supply line through which a second excitation current, which is a current having a predetermined waveform, is input;
a first input signal line through which a first input signal indicating a logic state is input;
a first pulse train generation circuit including a first Josephson junction and configured to output a first pulse train which is a pulse train generated by the first Josephson junction on the basis of the predetermined frequency of the first excitation current, the waveform of the second excitation current, and the logic state indicated by the first input signal, the first pulse train having a repetition frequency corresponding to the predetermined frequency;
a second pulse train generation circuit including a second Josephson junction and configured to output a second pulse train which is a pulse train generated by the second Josephson junction on the basis of the predetermined frequency of the first excitation current, the second pulse train having a repetition frequency corresponding to the predetermined frequency;
and
an output pulse train generation circuit including a third Josephson junction and configured to output an output pulse train in which a waveform of the first pulse train is shaped by the repetition frequency of the second pulse train.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/842,688Filed 22 Feb 2023
Priority: JP 2022-0336364 Mar 2022
Published: US 2025/0183897 A15 Jun 2025
Granted: 7 Apr 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

H03K 19/195
Using specified components: using superconductive devices
G06N 10/00
Quantum computing, i.e. information processing based on quantum-mechanical phenomena
H03K 3/38
Generators characterised by the type of circuit or by the means used for producing pulses: by the use, as active elements, of superconductive devices
H03K 17/92
Characterised by the components used: by the use, as active elements, of superconductive devices