Two-Qubit Gate Using Inductive Longitudinal Coupling

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Solution Overview

Problem

Existing methods for implementing two-qubit gates in quantum computing suffer from low precision due to the properties of qubits, particularly when using capacitors for qubit coupling.

Innovation Solution

A method and circuit are provided to implement a two-qubit gate by applying quantum control signals to data qubits, specifically adjusting these signals to activate longitudinal coupling between the qubits within a predetermined time, thereby improving precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If capacitor coupling is used to construct a two-qubit gate, then the gate can be implemented, but the precision is low due to qubit properties

Engineering Contradiction:

Improveprecision of two-qubit gateVSAvoiderror rate of two-qubit gate

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent changes the coupling parameter from capacitor-based electrical coupling to inductor-based magnetic coupling. By using inductors with specific inductance values (e.g., 10 nH to 100 nH) and adjusting the coupling strength through inductor geometry and positioning, the system achieves more precise and controllable two-qubit gate operations with reduced error rates

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the capacitor-based electrical field coupling mechanism with an inductor-based magnetic field coupling mechanism. This substitution leverages magnetic coupling through inductors to achieve better precision in two-qubit gate implementation, overcoming the limitations of capacitor coupling due to qubit properties

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly reduces errors in the two-qubit gate by minimizing other types of coupling, resulting in improved precision and addressing the issue of low precision in existing two-qubit gate implementations.

Implementation Method 1

applying a first quantum control signal to a first data qubit; applying a second quantum control signal to a second data qubit; and activating, by means of adjusting the first quantum control signal and the second quantum control signal, longitudinal coupling between the first data qubit and the second data qubit within a predetermined time

Methodology Applied

Scientific EffectQuantum control:

Data Source

PatentEP4564240A1Two-qubit gate implementing method and circuit, quantum device, and quantum chip

Publication Date: 2025.06.04 Z-AXIS PTE LTD

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AI summary

Disclosed are a method and a circuit for implementing a two-qubit gate, a quantum device, and a quantum chip. The method includes: applying a first quantum control signal to a first data qubit; applying a second quantum control signal to a second data qubit; and activating, by means of adjusting the first quantum control signal and the second quantum control signal, longitudinal coupling between the first data qubit and the second data qubit within a predetermined time, so as to implement the two-qubit gate. The present disclosure solves the technical problem in the related art of low precision of the two-qubit gate.