Quantum Gate Bayesian Tuning with Prior-Guided Qubit Calibration

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Solution Overview

Problem

Current methods for tuning quantum gates in quantum computers are inefficient due to the need for substantial input data and inability to reduce data requirements, leading to high latency in calibration processes.

Innovation Solution

The Bayesian Adaptive Control for RB (BACRONYM) method uses prior information to update control-parameter values, incorporating uncertainty in the objective function, and re-interrogating qubits to optimize gate fidelity, reducing data needs and improving calibration efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional tuning methods are used for quantum gates, then comprehensive calibration can be achieved, but the operational time required is excessive and data requirements are substantial

Engineering Contradiction:
Improvegate fidelityVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The method performs preliminary actions by obtaining a prior distribution over features through previous adaptive or non-adaptive interrogation of qubits. This prior information is then reused in subsequent tuning iterations, eliminating the need to start from scratch each time and significantly reducing the total calibration time while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The method implements feedback by computing an objective function that quantifies operational quality of the quantum gate, then using this feedback to update control-parameter values. The prior distribution is expanded to incorporate uncertainty in the objective function, and the process repeats with re-interrogation of qubits, creating a closed-loop system that efficiently converges to optimal gate fidelity.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If traditional tuning methods are used for quantum gates, then adequate calibration can be achieved, but substantial input data is required

Engineering Contradiction:
Improvegate fidelityVSAvoiddata requirements
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The method recovers and reuses data that would otherwise be discarded. By obtaining a prior distribution through previous interrogation and expanding it to incorporate new information, the method recovers valuable information from earlier measurements and applies it to subsequent tuning steps, dramatically reducing the total quantity of new data needed while maintaining measurement precision.

Inventive Principle:
Principle #34Discarding and recovering

3Measurement precision

If iterative tuning process is performed with updated control parameters, then gate operational quality improves, but the process complexity increases

Engineering Contradiction:
Improveoperational qualityVSAvoidtuning process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The method systematically changes parameters by updating control-parameter values based on the computed objective function and expanding the prior distribution to incorporate uncertainty. This structured parameter change approach improves operational quality while managing process complexity through the use of Bayesian statistical frameworks that provide a systematic way to handle the iterative process.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10469087B1Bayesian tuning for quantum logic gates
Publication Date: 2019.11.05 MICROSOFT TECHNOLOGY LICENSING LLC
  • US10469087B1 patent drawing
  • US10469087B1 patent drawing
  • US10469087B1 patent drawing

AI summary

A method for tuning a quantum gate of a quantum computer comprises interrogating one or more qubits of the quantum computer using stored control-parameter values and yielding new data. The method further comprises computing an objective function quantifying operational quality of the quantum gate at the stored control-parameter values, such computing employing the new data in addition to a prior distribution over features used to compute the objective function. Here, the prior distribution may be obtained by previous adaptive or non-adaptive interrogation of the one or more qubits, for instance. The method further comprises updating the stored control-parameter values, expanding the prior distribution to incorporate uncertainty in the objective function at the updated control-parameter values, re-interrogating the one or more qubits using the updated control-parameter values, and re-computing the objective function using the expanded prior distribution.