Quantum Logic Circuit Encoding for QUBO Problem Solving

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Solution Overview

Problem

Current methods for solving computational problems, particularly discrete optimization and constraint satisfaction problems, are inefficient as they often require traditional classical solvers that struggle with the complexity of these issues, especially when dealing with quadratic unconstrained binary optimization problems.

Innovation Solution

The approach involves encoding a logic circuit representation of a computational problem as a discrete optimization problem, specifically a quadratic unconstrained binary optimization (QUBO) problem, and solving it using a quantum processor, which enables the use of adiabatic quantum computation or quantum annealing to find the optimal solution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If logic circuit representations are used to solve computational problems, then the problem can be modeled systematically, but the complexity of finding optimal solutions increases due to the need for precise control of quantum states

Engineering Contradiction:
Improvesolution accuracyVSAvoidquantum state control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces direct quantum state control mechanisms with an energy minimization framework. Instead of precisely manipulating quantum states through complex control mechanisms, the system formulates computational problems as energy landscapes where the ground state naturally represents the optimal solution, substituting mechanical control with thermodynamic principles

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transforms the problem representation by changing parameters from direct logical variables to energy states. By mapping logical operations to energy functions and using continuous energy minimization instead of discrete quantum state transitions, the system simplifies the control requirements while maintaining computational equivalence

Inventive Principle:
Principle #35Parameter changes

2Productivity

If classical solvers are used to solve discrete optimization problems, then the computational process is straightforward, but they are inefficient in finding optimal solutions for complex problems

Engineering Contradiction:
Improvesolution finding efficiencyVSAvoidsolver complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces classical iterative optimization algorithms with quantum mechanical principles. Instead of using classical solvers that systematically explore the solution space through computation, the system uses quantum tunneling and energy minimization to directly reach the ground state, substituting computational iteration with physical evolution

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes quantum phase transitions and adiabatic evolution to solve optimization problems. By slowly evolving the system Hamiltonian from an initial easy-to-solve state to the problem Hamiltonian, the system exploits quantum phase transitions to maintain the ground state throughout the evolution, efficiently finding optimal solutions without classical computational complexity

Inventive Principle:
Principle #36Phase transitions

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 method effectively executes the logic circuit to solve the original computational problem by minimizing the energy of the system, providing a more efficient and accurate solution to complex optimization and constraint satisfaction problems compared to classical solvers.

Implementation Method 1

evolving a system from a known initial Hamiltonian to a final Hamiltonian by gradually changing the Hamiltonian

Methodology Applied
Scientific EffectQuantum annealing:

Implementation Method 2

AQC is a special case of quantum annealing for which the system, ideally, begins and remains in its ground state throughout an adiabatic evolution

Methodology Applied
Scientific EffectAdiabatic quantum computation:

Implementation Method 3

quantum effects, such as quantum tunneling, to reach a global energy minimum more accurately and/or more quickly

Methodology Applied
Scientific EffectQuantum tunneling:

Data Source

PatentUS20110231462A1Systems and methods for solving computational problems
Publication Date: 2011.09.22 D WAVE SYSTEMS INC
  • US20110231462A1 patent drawing
  • US20110231462A1 patent drawing
  • US20110231462A1 patent drawing

AI summary

Solving computational problems may include generating a logic circuit representation of the computational problem, encoding the logic circuit representation as a discrete optimization problem, and solving the discrete optimization problem using a quantum processor. Output(s) of the logic circuit representation may be clamped such that the solving involves effectively executing the logic circuit representation in reverse to determine input(s) that corresponds to the clamped output(s). The representation may be of a Boolean logic circuit. The discrete optimization problem may be composed of a set of miniature optimization problems, where each miniature optimization problem encodes a respective logic gate from the logic circuit representation. A quantum processor may include multiple sets of qubits, each set coupled to respective annealing signal lines such that dynamic evolution of each set of qubits is controlled independently from the dynamic evolutions of the other sets of qubits.