Surface Code Encoder with Fewer CNOT Gates and Measurements
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Solution Overview
Problem
Current encoding methods for qubits in calculating devices are inefficient, requiring numerous CNOT gates and ancilla qubits, leading to high error detection complexity and resource consumption.
Innovation Solution
An encoder with a controller that performs a specific sequence of two-qubit gates on multiple qubits to encode a surface code with a code distance of 3, reducing the number of necessary CNOT gates and stabilizer measurements, thereby enhancing encoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encoding methods are used with numerous CNOT gates and ancilla qubits, then encoding can be performed, but resource consumption and error detection complexity increase significantly
Solution Approach 1:
The encoding process is divided into distinct stages: preparing computational basis states, applying specific two-qubit gate sequences (CNOT gates in particular patterns), and performing stabilizer measurements. This segmentation allows each step to be optimized independently, reducing overall complexity while maintaining fault tolerance.
Solution Approach 2:
The patent prepares computational basis states |0⟩ and |1⟩ in advance before performing the actual encoding operations. This preliminary preparation simplifies the subsequent encoding steps by ensuring qubits are in known states, reducing the complexity of error detection during the main encoding process.
2Manufacturing precision
If more CNOT gates are used for encoding, then encoding accuracy improves, but the number of operations and time required increase
Solution Approach 1:
The patent changes the parameters of the encoding process by using a specific sequence of two-qubit gates with optimized coupling strengths and interaction times. By adjusting these parameters, the encoding achieves high accuracy without requiring an excessive number of gate operations, thus reducing encoding time.
Solution Approach 2:
The encoding process maintains continuous useful action by performing stabilizer measurements concurrently with gate operations where possible, and by using ancilla qubits that remain engaged in the encoding process throughout. This continuity reduces idle time and optimizes the overall encoding duration while maintaining accuracy.
Data Source
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AI summary
According to one embodiment, an encoder includes a first element part and a controller. The first element part includes a first qubit, a second qubit couplable with the first qubit, a third qubit couplable with the second qubit, a fourth qubit couplable with the third qubit, a fifth qubit couplable with the fourth qubit, a sixth qubit couplable with the fifth qubit, a seventh qubit couplable with the sixth qubit, an eighth qubit couplable with the seventh qubit, and a ninth qubit couplable with the eighth qubit. The controller is configured to perform a first control. The first control includes encoding a surface code having a code distance of 3.