Qubit Relaxation Time Screening via Frequency-Shifted Measurements

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Solution Overview

Problem

Existing techniques for analyzing qubit coherence parameters are cumbersome, time-consuming, and resource-intensive, leading to unnecessary diagnostics and waste of quantum resources due to the fluctuating nature of qubit coherence caused by two-level systems, which affects the scheduling and mapping of quantum jobs.

Innovation Solution

A system and method that employs frequency-shifted qubits using methods like flux tuning, Autler-Townes effect, DC electric field, or mechanical strain to probe the frequency space around the qubit frequency, enabling rapid determination of true average relaxation times and understanding qubit coherence parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional techniques are used to analyze qubit coherence parameters, then measurement precision can be achieved, but the process becomes time-consuming and resource-intensive

Engineering Contradiction:

Improvequbit coherence parametersVSAvoiddiagnostic time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the frequency space into multiple discrete frequency points around the qubit frequency. Instead of performing a single comprehensive measurement, the system divides the coherence analysis into multiple measurements at different frequency offsets (e.g., ω0 - Δω, ω0, ω0 + Δω), which can be performed rapidly and independently, then combined to characterize the full coherence behavior.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs periodic modulation of the qubit frequency using flux tuning or other control mechanisms. By applying periodic flux modulation at different frequencies and measuring the response, the system can rapidly probe the coherence properties without requiring long continuous measurement periods, thus reducing diagnostic time while maintaining precision.

Inventive Principle:

Principle #19Periodic action

2Loss of information

If comprehensive qubit coherence analysis is performed, then understanding of qubit usability is improved, but quantum resources are wasted due to fluctuating coherence

Engineering Contradiction:

Improvequbit usability informationVSAvoidquantum resources

Core Design Contradiction:

Loss of informationVSLoss of energy

Solution Approach 1:

The patent performs preliminary coherence measurements at multiple frequency points before scheduling quantum jobs. By characterizing the coherence properties in advance across different frequency offsets, the system creates a predictive model of qubit usability that informs job scheduling decisions, preventing waste of quantum resources on qubits with poor coherence at the required operating frequency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where coherence measurement results are fed back into the job scheduling and mapping system. The measured coherence parameters at different frequency points are used to dynamically adjust which qubits are assigned to which quantum jobs, ensuring that quantum resources are allocated efficiently based on actual measured performance rather than static assumptions.

Inventive Principle:

Principle #23Feedback

3Loss of information

If frequency-shifted measurements are performed to probe frequency space, then qubit coherence understanding is improved, but measurement complexity increases

Engineering Contradiction:

Improvefrequency space characteristicsVSAvoidmeasurement system

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The patent uses flux tuning as an intermediary mechanism to shift the qubit frequency to different operating points. By controlling the flux through the SQUID loop, the system can rapidly and precisely tune the qubit frequency to offset frequencies (ω0 ± Δω) without requiring physical reconfiguration of the qubit circuit, thus simplifying the measurement system while enabling comprehensive frequency space probing.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 allows for more informed scheduling and mapping of quantum jobs by providing rapid forecasting of qubit usability and understanding of qubit coherence fluctuations, reducing waste and improving resource utilization in quantum computing.

Implementation Method 1

Methodology Applied

Scientific EffectAutler-Townes effect:

Implementation Method 2

Methodology Applied

Scientific EffectFlux tuning:

Data Source

PatentUS12608441B2Screening for fluctuating energy relaxation times

Publication Date: 2026.04.21 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

One or more systems, devices, computer program products and/or computer-implemented methods of use provided herein relate to determining estimated true relaxation times of qubits absent measurement of entire T1 decay times of the qubits. A system can comprise a memory that stores computer executable components; and a processor that executes the computer executable components stored in the memory, wherein the computer executable components are executable to cause, by the processor, one or more energy relaxation measurements, using a pulse generation, at the qubit frequency for a qubit and at a plurality of shifted frequencies for the qubit, and to determine, by the processor, a true average relaxation time of the qubit based on the plurality of energy relaxation measurements.