Qubit Noise Estimation Using Circuit Success and Gate Counts

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Computation processing over noisy intermediate-scale quantum (NISQ) computers is affected by noise, which changes over time, and frequent measurement of noise using existing methods like randomized benchmarking (RB) can delay intended computations due to the time-consuming nature of these measurements.

Innovation Solution

A noise information estimation method that involves acquiring output distributions from multiple quantum circuit executions, determining execution success/failure based on deviation from a uniform distribution, and estimating noise information using the number of applied quantum gates to efficiently grasp the latest noise state without prolonged measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If noise state is frequently measured using existing methods like randomized benchmarking, then the latest noise state can be obtained, but computation processing is delayed due to time-consuming measurements

Engineering Contradiction:
Improvenoise state measurement accuracyVSAvoidcomputation processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent introduces an intermediary method (shadow tomography) that uses a small number of quantum circuit executions to indirectly estimate noise states. Instead of directly measuring noise through time-consuming randomized benchmarking, the system uses output distributions from regular quantum computations as intermediaries to infer noise characteristics, thereby avoiding the time penalty while maintaining measurement accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a simplified copy of the noise measurement process by using shadow tomography techniques. Rather than executing full randomized benchmarking sequences, the system uses compressed representations (shadows) of quantum states obtained from regular computations to reconstruct noise information, significantly reducing the time required while preserving measurement precision.

Inventive Principle:
Principle #26Copying

2Loss of information

If noise measurement is performed using existing methods, then noise information can be acquired, but quantum computer availability deteriorates due to measurement congestion

Engineering Contradiction:
Improvenoise information acquisitionVSAvoidquantum computer availability
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The patent merges noise measurement with regular quantum computation processing. By extracting noise information from output distributions of standard quantum circuits executed for computational purposes, the system eliminates the need for separate dedicated noise measurement sessions. This integration ensures that noise information acquisition does not compete for quantum computer resources, thereby maintaining high availability while continuously gathering noise data.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If quantum circuits are optimized based on latest noise state, then computation success rate improves, but frequent noise measurement causes computation postponement

Engineering Contradiction:
Improvecomputation success rateVSAvoidcomputation processing duration
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent establishes continuous noise monitoring through shadow tomography that operates in the background during regular quantum computations. This continuous passive measurement ensures that noise state information is always available for circuit optimization without interrupting the computational workflow. The system maintains computation success rate by continuously adapting to noise changes while avoiding postponement through seamless integration of measurement and computation processes.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP4632632A1Noise information estimation program, noise information estimation method, and information processing apparatus
Publication Date: 2025.10.15 FUJITSU LTD
  • EP4632632A1 patent drawingFigure 1
  • EP4632632A1 patent drawingFigure 2
  • EP4632632A1 patent drawingFigure 3

AI summary

A noise information estimation program including instructions which, when executed by a computer, cause the computer to execute processing including: acquiring a plurality of output distributions that indicate distributions of output states of a plurality of qubits that correspond to each of a plurality of quantum circuits when each of the plurality of quantum circuits is executed a plurality of times for the plurality of qubits; determining execution success/failure of each of the plurality of quantum circuits, based on a deviation degree between each of the plurality of output distributions and a uniform distribution; and estimating information related to noise of each of the plurality of qubits, based on a determination result of the execution success/failure of each of the plurality of quantum circuits and a number of quantum gates applied to each of the plurality of qubits in each of the plurality of quantum circuits.