Quantum Hamiltonian Embedding for Low-Qubit Molecular Simulation

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Solution Overview

Problem

Current quantum computers face limitations in simulating larger molecules due to hardware constraints such as the number of qubits, gate depth, and gate fidelity, leading to high computational costs and errors in molecular simulations.

Innovation Solution

The system reduces the number of quantum circuit gate operations by modifying the Hamiltonian to improve embedding on a quantum annealer, using spin coherent states and parametrizing coordinates in Pauli Z rotations, which reduces the number of qubits required and minimizes errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional quantum computing methods are used to simulate molecules, then computational accuracy can be maintained, but the number of qubits and gate operations required becomes prohibitively large

Engineering Contradiction:
Improvecomputational accuracyVSAvoidnumber of qubits
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies parameter changes by modifying the Hamiltonian representation from conventional forms to spin coherent state parametrization with Pauli Z rotations. This transformation changes the mathematical parameters of the quantum problem, enabling more efficient encoding of molecular information that reduces the number of qubits needed while preserving computational accuracy through the variational principle.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the quantum computation by separating the Hamiltonian into specific components that can be embedded efficiently on quantum annealers. By dividing the problem into manageable segments compatible with hardware constraints, the method reduces the overall resource requirements while maintaining solution accuracy.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If more gate operations are performed to achieve full configuration interaction equivalent energy, then computational accuracy improves, but the computational cost and error accumulation increase

Engineering Contradiction:
Improveenergy calculation accuracyVSAvoidcomputational efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies partial action by using a variational approach that achieves sufficient accuracy without requiring complete configuration interaction. The method performs a controlled subset of quantum operations that provide adequate precision for molecular simulations, avoiding the excessive computational cost of full CI while maintaining practical accuracy through the variational principle.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

By changing the parameterization of the quantum state and Hamiltonian, the method achieves the same physical insights with fewer gate operations. The spin coherent state representation and Pauli Z rotations transform the problem parameters to reduce operational complexity while preserving the essential physics needed for accurate energy calculations.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If the Hamiltonian is modified to improve embedding on quantum annealers, then the number of qubits required decreases, but the complexity of the transformation increases

Engineering Contradiction:
Improvenumber of qubitsVSAvoidHamiltonian transformation complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent systematically changes the parameters of the Hamiltonian through spin coherent state parametrization and Pauli Z rotations. This structured parameter transformation, while mathematically complex, follows established quantum mechanical principles and provides a systematic pathway to reduce qubit requirements while maintaining the physical fidelity of the molecular simulation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11301770B2Methods and systems for solving a problem on a quantum computer
Publication Date: 2022.04.12 OTI LUMIONICS INC
  • US11301770B2 patent drawing
  • US11301770B2 patent drawing
  • US11301770B2 patent drawing

AI summary

A method of solving a problem can include providing a fermionic Hamiltonian, transformation of the fermionic Hamiltonian to qubit operators, transformation of the fermionic Hamiltonian in qubit operators to a mean-field Hamiltonian, and embedding the Hamiltonian onto a quantum computer. Such systems and methods may improve upon existing methods for solving electronic structure problems on a computer by adapting the problem to available hardware, reducing computational cost, and reducing the number of required qubits to solve electronic structure problems for larger number of atoms.