Josephson Junction Laser Annealing for Multi-Qubit Frequency Tuning

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Solution Overview

Problem

Existing multi-qubit systems face challenges in precisely tuning qubit frequencies due to frequency collisions, which are traditionally addressed using adjustable magnetic fields that introduce noise and complexity.

Innovation Solution

The method involves annealing Josephson junctions using localized laser annealing to adjust qubit frequencies independently, allowing for precise tuning without affecting other components, and utilizing a historical database for accurate adjustments based on previous parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If adjustable magnetic fields are used to address frequency collisions, then frequency tuning capability is improved, but system complexity and noise increase

Engineering Contradiction:

Improvefrequency tuning capabilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the frequency tuning function from the magnetic field system and implements it through localized laser annealing of Josephson junctions. This removes the complex magnetic field adjustment mechanism while retaining the essential frequency tuning capability through a simpler thermal annealing process.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/electromagnetic field-based frequency adjustment system with a thermal annealing system. By using localized laser heating to anneal Josephson junctions, the system substitutes complex magnetic field control with a more manageable thermal process that achieves the same frequency tuning objective.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If adjustable magnetic fields are used to address frequency collisions, then frequency tuning capability is improved, but noise is introduced

Engineering Contradiction:

Improvefrequency tuning capabilityVSAvoidnoise

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the magnetic field system that generates noise while preserving frequency tuning capability through laser annealing. By extracting the unnecessary magnetic field component, the harmful noise is eliminated while the essential function of frequency adjustment remains through thermal processing of Josephson junctions.

Inventive Principle:

Principle #2Taking out (Extraction)

3Manufacturing precision

If localized annealing is used to adjust Josephson junctions, then manufacturing precision is improved, but process complexity increases

Engineering Contradiction:

Improvefrequency adjustment precisionVSAvoidannealing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by using localized laser annealing to modify only specific Josephson junctions that require frequency adjustment. This concentrated approach achieves high manufacturing precision for frequency tuning while avoiding the need to process entire qubit systems, thereby managing process complexity through selective application.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The localized annealing process allows each Josephson junction to be independently adjusted to its optimal frequency characteristics. The self-service principle is applied by enabling individual junctions to be tuned without requiring complex coordinated adjustment of entire qubit assemblies, simplifying the overall process while maintaining high precision.

Inventive Principle:

Principle #25Self-service

4Reliability

If frequency tuning is performed to reduce frequency collisions, then reliability is improved, but processing time increases

Engineering Contradiction:

Improvecoherence timeVSAvoidprocessing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing frequency tuning through laser annealing during or after the fabrication process, before the qubits are fully assembled and operational. This advance tuning ensures optimal frequency separation is achieved upfront, improving reliability while minimizing the need for time-consuming adjustments during later system operation or testing.

Inventive Principle:

Principle #10Preliminary 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 approach enables precise frequency tuning of qubits, reducing frequency collisions and improving coherence time by allowing independent adjustments of qubit frequencies, thereby enhancing the performance of multi-qubit chips.

Implementation Method 1

annealing the first Josephson junction using localized annealing of the first Josephson junction

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

annealing a first Josephson junction of a first qubit of the plurality of qubits

Methodology Applied

Scientific EffectAnnealing: Annealing

Data Source

PatentUS12414482B2Frequency tuning of multi-qubit systems

Publication Date: 2025.09.09 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

The invention includes methods, and the structures formed, for multi-qubit chips. The methods may include annealing a Josephson junction of a qubit to either increase or decrease the frequency of the qubit. The conditions of the anneal may be based on historical conditions, and may be chosen to tune each qubit to a desired frequency.