Ferromagnetic Domain-Wall Qubit Tuning With Lower Flux Noise

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Solution Overview

Problem

Existing superconducting quantum computing apparatuses face challenges in efficiently controlling the resonant frequency of multiple qubits due to magnetic flux noise and spatial constraints from numerous flux lines, limiting the scalability and performance of multi-qubit chips.

Innovation Solution

The apparatus incorporates frequency tunable devices connected to each other and a ferromagnetic film with adjustable magnetic domain walls, controlled by a current-induced spin-transfer torque, allowing for simultaneous resonant frequency adjustment of qubits without continuous current application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple flux lines are used to control resonant frequency of multiple qubits, then frequency control capability is improved, but magnetic flux noise increases

Engineering Contradiction:

Improvefrequency control capabilityVSAvoidmagnetic flux noise

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

Multiple flux lines are merged into a single ferromagnetic film structure. The film is divided into multiple regions that can be independently magnetized, allowing each region to control the resonant frequency of corresponding qubits. This consolidation reduces the number of separate control lines needed and minimizes magnetic flux noise while maintaining the ability to independently tune multiple qubit frequencies.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The ferromagnetic film acts as an intermediary between control currents and qubit resonant frequencies. Instead of directly coupling multiple flux lines to multiple qubits, the film mediates this interaction by converting electrical currents into localized magnetic fields that selectively adjust qubit frequencies. This intermediate step reduces direct magnetic interference and noise.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple flux lines are used to control resonant frequency of multiple qubits, then frequency control capability is improved, but spatial constraints increase

Engineering Contradiction:

Improvefrequency control capabilityVSAvoidspatial constraints

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The control mechanism transitions from multiple one-dimensional flux lines to a two-dimensional ferromagnetic film. By utilizing the planar structure of the film with spatially separated magnetizable regions, the system achieves multiple frequency control points without requiring proportional increases in linear space, effectively using area efficiency to reduce spatial constraints.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If continuous current is applied to adjust resonant frequency, then frequency tuning precision is improved, but energy consumption increases

Engineering Contradiction:

Improvefrequency tuning precisionVSAvoidenergy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Instead of applying continuous current to maintain resonant frequency tuning, the system uses periodic or pulsed current application. The ferromagnetic film retains its magnetized state after current pulses, allowing frequency adjustments to be maintained without continuous energy input. This approach achieves precise frequency tuning while significantly reducing energy consumption compared to continuous current application.

Inventive Principle:

Principle #19Periodic action

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 method stabilizes resonant frequency control, reduces magnetic flux noise, and overcomes spatial constraints, enabling efficient operation of large-scale superconducting quantum computing systems.

Implementation Method 1

The control circuit may be configured to move the position of the magnetic domain wall along the ferromagnetic film by applying a current to the ferromagnetic film to induce a spin-transfer torque (STT) phenomenon.

Methodology Applied

Scientific EffectSpin-transfer torque:

Implementation Method 2

a ferromagnetic film disposed adjacent to the frequency tunable devices and having an up magnetic domain or a down magnetic domain

Methodology Applied

Scientific EffectMagnetic field generation: Magnetic Field

Data Source

PatentUS12471503B2Superconducting quantum computing apparatus including frequency tunable devices

Publication Date: 2025.11.11 SAMSUNG ELECTRONICS CO LTD

AI summary

A superconducting computing apparatus includes: frequency tunable devices connected to each other and arranged in a shape; a ferromagnetic film disposed adjacent to the frequency tunable devices and having an up magnetic domain or a down magnetic domain; and a control circuit configured to adjust a position of a magnetic domain wall in the ferromagnetic film by applying a current to the ferromagnetic film, wherein the position of the magnetic domain wall controls a resonant frequency of the frequency tunable devices.