Logical Qubit Rotation Control Using Multi-Pattern Gate Teleportation
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Solution Overview
Problem
Existing quantum computing systems face challenges in achieving high accuracy for rotation gate operations on logical qubits due to control errors in the preparation of resource states, particularly in high-precision rotation techniques like the STAR architecture, which affect the precision of gate teleportation circuits.
Innovation Solution
A method is introduced to improve the accuracy of rotation gate operations by generating multiple rotation direction patterns for physical qubits constituting a logical qubit, using a gate teleportation circuit to perform the rotation operation multiple times with different direction combinations, and applying correction processes when necessary, such as logical X operators or virtual Z gates, to cancel out rotation errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-precision rotation technique using virtual Z gate is used to prepare resource state, then the rotation precision should be improved, but control errors still occur in the rotation gate operation on physical qubits which propagate to logical qubit errors
Solution Approach 1:
The patent segments the rotation operation by dividing it into multiple smaller rotation steps. Instead of performing a single large rotation that is prone to control errors, the rotation is broken down into multiple smaller rotations applied sequentially to different physical qubits. This segmentation reduces the cumulative error in each individual rotation step while achieving the same total rotation angle, thereby improving the reliability of resource state preparation.
Solution Approach 2:
The patent changes the parameters of the rotation operation by adjusting the rotation angles and the number of rotation steps based on the target rotation angle. By optimizing these parameters, the system can achieve high-precision rotations with minimized control errors. The virtual Z gate technique is enhanced by dynamically adjusting rotation parameters to compensate for known error sources, improving both precision and reliability.
2Measurement precision
If multiple rotation direction patterns are generated and multiple gate teleportation circuits are executed, then the accuracy of rotation gate operation is improved, but the computation time and resource consumption increase
Solution Approach 1:
The patent applies preliminary action by pre-generating multiple rotation direction patterns before executing the gate teleportation circuits. These patterns are prepared in advance based on the target rotation angle, allowing the system to systematically explore different rotation paths. By having the patterns ready beforehand, the system avoids redundant computations during execution and can efficiently select the most promising patterns, reducing overall computation time while maintaining high accuracy.
Solution Approach 2:
The patent implements feedback mechanisms where the results from previous gate teleportation circuit executions are used to inform subsequent rotations. By measuring the actual rotation outcomes and comparing them with expected values, the system can adjust subsequent rotation patterns to compensate for accumulated errors. This feedback loop enables the system to achieve high accuracy without requiring an excessive number of iterations, thus balancing precision with computation time.
Data Source
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AI summary
An information processing apparatus generates N rotation direction patterns each indicating a combination of rotation directions respectively for first physical qubits constituting a second logical qubit. The information processing apparatus determines a physical rotation angle for the first physical qubits so as to rotate the state of the first logical qubit by a second logical rotation angle that is 1/N of a first logical rotation angle by which the state of the first logical qubit is to be rotated. The information processing apparatus instructs a quantum computer to generate a resource state by rotating the first physical qubits according to each of the N rotation direction patterns. Each time the resource state is generated, the information processing apparatus instructs the quantum computer to perform a rotation operation on the first logical qubit by the second logical rotation angle using the generated resource state.