Automated Quantum Circuit Optimization with Continuous Parameters

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Solution Overview

Problem

Existing techniques struggle to efficiently optimize large-scale quantum circuits, particularly those with continuous parameters, which are essential for quantum computations that outperform classical computers.

Innovation Solution

The development of automated optimization methods that handle continuous gate parameters, applying a set of carefully chosen heuristics to reduce gate counts in quantum circuits, while preserving the basic layout of underlying quantum algorithms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If existing optimization techniques are applied to large-scale quantum circuits with continuous parameters, then some level of optimization is achieved, but the optimization efficiency is insufficient and gate count reduction is limited

Engineering Contradiction:
Improveoptimization efficiencyVSAvoidgate count
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent transforms the continuous parameter optimization problem into a discrete optimization problem by parameterizing rotation gates with discrete variables. This allows the use of efficient discrete optimization algorithms while maintaining the ability to represent continuous gate operations, thereby improving optimization efficiency without sacrificing gate count reduction capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the quantum circuit optimization problem into independent rotation gate parameter optimizations. By treating each rotation gate's parameters as separate optimization variables, the method enables efficient local optimizations that can be combined to achieve global circuit optimization, significantly improving scalability to large-scale circuits

Inventive Principle:
Principle #1Segmentation

2Speed

If automated optimization methods are used to reduce gate counts, then optimization speed improves, but preserving the basic layout of underlying quantum algorithms becomes more difficult

Engineering Contradiction:
Improveoptimization speedVSAvoidalgorithm layout preservation
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary layout preservation constraints before the optimization process begins. By establishing which structural elements of the quantum algorithm must be preserved and encoding these constraints into the optimization framework, the method enables rapid optimization while maintaining the essential layout and logical structure of the underlying quantum algorithms

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If more aggressive optimization techniques are applied to achieve better gate count reduction, then optimization quality improves, but the time required for optimization increases significantly

Engineering Contradiction:
Improveoptimization qualityVSAvoidoptimization time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies partial optimization actions by focusing computational resources on optimizing only the critical rotation gate parameters that have the most significant impact on gate count, rather than exhaustively optimizing all parameters. This selective approach achieves high optimization quality for the most important elements while keeping the total optimization time manageable

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3698297B1Automated optimization of large-scale quantum circuits with continuous parameters
Publication Date: 2025.04.09 IONQ INC
  • EP3698297B1 patent drawingFigure 1~2
  • EP3698297B1 patent drawingFigure 3
  • EP3698297B1 patent drawingFigure 4

AI summary

The disclosure describes the implementation of automated techniques for optimizing quantum circuits of the size and type expected in quantum computations that outperform classical computers. The disclosure shows how to handle continuous gate parameters and report a collection of fast algorithms capable of optimizing large-scale-scale quantum circuits. For the suite of benchmarks considered, the techniques described obtain substantial reductions in gate counts. In particular, the techniques in this disclosure provide better optimization in significantly less time than previous approaches, while making minimal structural changes so as to preserve the basic layout of the underlying quantum algorithms. The results provided by these techniques help bridge the gap between computations that can be run on existing quantum computing hardware and more advanced computations that are more challenging to implement in quantum computing hardware but are the ones that are expected to outperform what can be achieved with classical computers.