Local Quantum Circuit Optimization for Accurate Time Evolution
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Solution Overview
Problem
Existing quantum circuits for expressing time evolution operators face challenges in reducing the number of operations, leading to increased scale and depth, which results in errors and prolonged calculation times, especially in quantum computers with several hundred qubits.
Innovation Solution
The method involves creating a first, second, and third quantum circuit with a reduced size, calculating parameter solutions to minimize a cost function, and setting a new quantum circuit to express the time evolution operator, thereby reducing the number of quantum gates and operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a quantum circuit is created to express a predetermined action (such as time evolution operator), then the calculation accuracy is improved, but the number of quantum gates increases leading to more operations and accumulated errors
Solution Approach 1:
The patent applies segmentation by dividing the quantum circuit into multiple layers, where each layer contains a limited number of quantum gates. This layering approach allows the circuit to express complex predetermined actions while controlling the number of gates in each layer, thereby reducing accumulated errors from environmental noise and interference.
Solution Approach 2:
The patent employs dynamics by using a variational quantum circuit with adjustable parameters that can be optimized through classical computation. The circuit structure allows dynamic adjustment of gate sequences and parameters to achieve the desired action with minimal gates, balancing accuracy and error reduction.
2Measurement precision
If the number of quantum gates is increased to express a predetermined action, then the action accuracy is improved, but the calculation time increases
Solution Approach 1:
By segmenting the quantum circuit into layers with controlled gate counts, the patent reduces the total number of gates required to achieve the predetermined action. This segmentation enables faster execution while maintaining accuracy through optimized layer structures.
Solution Approach 2:
The patent utilizes parameter optimization where classical computation adjusts quantum circuit parameters to achieve the desired action with fewer gates. This parameter tuning reduces calculation time while preserving action accuracy by finding optimal gate sequences.
3Productivity
If a quantum circuit with reduced operations is created, then the calculation time is reduced, but it becomes difficult to express the predetermined action accurately
Solution Approach 1:
The variational quantum circuit with adjustable parameters enables dynamic optimization to express predetermined actions accurately with reduced gates. The classical-quantum hybrid approach dynamically tunes parameters to maintain accuracy while minimizing operation count.
Solution Approach 2:
By changing and optimizing circuit parameters through classical computation, the patent achieves accurate expression of predetermined actions with fewer quantum gates. This parameter optimization allows the reduced circuit to compensate for fewer operations through smarter gate sequences.
4Adaptability or versatility
If the scale and depth of quantum circuit are increased to express predetermined action, then the action completeness is improved, but the number of operations increases leading to more errors
Solution Approach 1:
The patent segments the quantum circuit into layers with controlled depth and gate counts. This segmentation maintains action completeness by distributing operations across layers while limiting the number of gates in each layer, thereby reducing error accumulation from environmental noise and qubit interference.
Solution Approach 2:
The patent applies partial action by implementing a layered circuit that achieves the essential predetermined action with sufficient accuracy without requiring complete exhaustive operations. This approach reduces the total number of gates while maintaining adequate action expression.
Data Source
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AI summary
An information processing program causing a computer to execute: acquiring a first quantum circuit expressing an action of a time evolution operator regarding a target problem, a second quantum circuit having parameters and a smaller number of quantum gates than the first quantum circuit, and a third quantum circuit defining one or more quantum states being a part of quantum states regarding the target problem, in which each of the first, second, and third quantum circuits has a first size; creating first, second, and third local circuits each having a second size, by respectively reducing sizes of the first, second, and third quantum circuits to the second size smaller than the first size; calculating solutions of the parameters, so as to minimize a value of a cost function for each quantum state; and setting a quantum circuit expressing the action of the time evolution operator.