Quantum Circuit Qubit-Pair Selection for Faster Energy Estimation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional variational quantum eigensolver (VQE) techniques require excessive computation time due to deepening circuit length and increased parameters, leading to inefficient computation of energy expectation values in the ground state of molecules.
Innovation Solution
A quantum computation method that creates qubit pairs from orbitals with and without electrons, applying two-qubit gates only to pairs with high effect on energy expectation value, and iteratively updating parameters to minimize unnecessary gate operations and parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gate operations are applied to all qubit pairs to obtain accurate energy expectation value, then measurement precision is improved, but device complexity increases due to more parameters and deeper circuit length
Solution Approach 1:
The patent extracts and identifies only the essential qubit pairs that contribute significantly to the energy expectation value accuracy. By analyzing the Hamiltonian decomposition and selecting only relevant qubit pairs for gate operations, it removes unnecessary gates and parameters while maintaining measurement precision.
Solution Approach 2:
The patent applies different treatment to different qubit pairs based on their local importance. Instead of uniformly applying gate operations to all qubit pairs, it selectively applies two-qubit gates only to specific qubit pairs that have significant impact on the energy expectation value, thereby reducing overall circuit complexity while maintaining accuracy.
2Measurement precision
If circuit length is deepened to improve energy expectation value accuracy, then measurement precision is improved, but loss of time increases due to more iterations required
Solution Approach 1:
The patent removes unnecessary gate operations from the circuit by identifying and selecting only the essential qubit pairs that contribute to accuracy. This extraction of essential elements reduces the number of iterations needed while maintaining measurement precision, thereby reducing computation time.
3Measurement precision
If number of parameters is increased to improve energy expectation value accuracy, then measurement precision is improved, but device complexity increases due to more iterations required
Solution Approach 1:
The patent extracts and retains only the essential parameters associated with critical qubit pairs. By eliminating parameters related to non-essential qubit pairs, it reduces the total number of parameters while maintaining the accuracy of energy expectation value measurement.
Solution Approach 2:
The patent assigns parameters selectively to specific qubit pairs based on their local importance to the energy expectation value. This localized parameter assignment reduces the overall number of parameters while ensuring that accuracy-critical regions maintain sufficient parameterization.
4Measurement precision
If number of iterations is increased to improve energy expectation value accuracy, then measurement precision is improved, but loss of time increases due to more computation cycles
Solution Approach 1:
The patent removes unnecessary computational steps by identifying and eliminating non-essential qubit pairs from the iteration process. This extraction reduces the number of computation cycles required while maintaining the precision of energy expectation value calculation.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An information processing apparatus creates qubit pairs, each being formed by combining first and second qubits. A first qubit corresponds to a first orbital on which an electron is present in an initial arrangement. A second qubit corresponds to a second orbital on which no electron is present in the initial arrangement. The apparatus generates a quantum circuit that applies two-qubit gates to at least some of the qubit pairs. Each two-qubit gate generates, based on the value of a parameter, a superposition state of a first state in which the states of the first and second qubits are not switched and a second state in which these states are switched. The apparatus acquires an energy expectation value in the ground state of the molecule by causing a quantum computer to iteratively execute the quantum circuit.