Two-Qubit Gate Decomposition Using Supercontrolled Basis Gates
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Solution Overview
Problem
Conventional quantum circuit design approaches face challenges in accurately simplifying two-qubit operations due to their reliance on discrete single-qubit basis sets, leading to inaccuracies and inefficient performance.
Innovation Solution
A computer-implemented method that uses zero to multiple applications of a super controlled basis gate to approximately expand target two-qubit operations, allowing for automatic rewriting of the source quantum circuit into a deployed quantum circuit based on analysis of instances, improving processing performance and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional approaches use discrete single-qubit basis sets for expanding two-qubit operations, then the expansion can be performed, but accuracy is significantly reduced
Solution Approach 1:
The patent changes the fundamental parameter of the basis set from discrete single-qubit gates to continuous two-qubit operations characterized by parameters α, β, γ. This allows exact representation of two-qubit operations by matching these parameters directly, eliminating the accuracy loss inherent in discrete basis expansions.
Solution Approach 2:
The patent transitions from expanding two-qubit operations using only single-qubit gates (one-dimensional approach) to using two-qubit basis operations (adding a new dimension). This dimensional change enables direct representation of entangled states and correlations that cannot be captured by product states alone.
2Adaptability or versatility
If universal gates are used to expand two-qubit gates, then any operation can be implemented, but circuit simplification is not achieved due to varying and limited performance
Solution Approach 1:
The patent applies local quality by using different basis operations (CNOT, CZ, iSWAP) optimized for specific types of two-qubit operations. Instead of universally applying the same gate set, the method selects basis operations that locally match the characteristics of the target operation, enabling both universality and efficiency.
Solution Approach 2:
The patent segments the space of all two-qubit operations into distinct regions characterized by parameters α, β, γ, where each region can be efficiently implemented using a specific small number of basis gates. This segmentation allows the circuit to be optimized for each segment rather than using a single universal expansion for all operations.
3Device complexity
If conventional approaches simplify two-qubit gates using limited basis sets, then some gates can be simplified, but inaccuracies result from not considering performance problems of certain two-qubit gates
Solution Approach 1:
The patent implements feedback by using classical computation to analyze the parameters of the target two-qubit operation and determine the optimal decomposition into basis gates. This feedback loop ensures that the simplified circuit maintains high accuracy by selecting the best expansion based on the specific characteristics of the operation being simplified.
Data Source
AI summary
Techniques are provided for improving quantum circuits. The technology includes approximately expanding, by a system operatively coupled to a processor, using zero to a number of applications of a super controlled basis gate, a target two-qubit operation, with the approximately expanding resulting in instances of the target two-qubit operation corresponding to the zero to the number of applications, and the target two-qubit operation is part of a source quantum circuit associated with a quantum computer. The system analyzes the instances and the super controlled basis gate, and automatically rewrites the source quantum circuit into a deployed quantum circuit based on the analyzing.