Quantum Circuit Canary Ordering for Higher Execution Fidelity
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Solution Overview
Problem
Existing quantum computing systems face high error rates due to imperfect qubits and dynamic noise sources, leading to low fidelity in executing quantum applications, especially for circuits with more than 10 qubits, which is exacerbated by the variability and inconsistency of noise properties across quantum devices.
Innovation Solution
A quantum computing system uses a Clifford canary circuit to identify the correct ordering of quantum devices within an ensemble, leveraging classical simulation to determine the most likely output, thereby increasing execution fidelity by ordering devices based on their likelihood to produce the correct output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If quantum computers with more qubits are used to solve classically intractable problems, then computational power increases, but execution fidelity decreases due to higher error rates
Solution Approach 1:
The patent creates a canary circuit that is a simplified copy of the original quantum circuit, using only Clifford gates instead of the full gate set. This canary circuit serves as a proxy to identify noise patterns and characterize quantum devices without requiring execution of the full complex circuit, enabling fidelity assessment on large quantum systems
Solution Approach 2:
The canary circuit acts as an intermediary between the original quantum circuit and the noisy quantum hardware. By executing the canary circuit first to characterize device noise properties, the system can then use this information to correct or compensate for errors in the original circuit execution, separating the fidelity assessment function from the actual quantum computation
2Reliability
If error mitigation techniques are applied to reduce noise effects, then execution fidelity improves slightly, but remains extremely small for quantum circuits with more than 10 qubits
Solution Approach 1:
The patent segments the quantum circuit into two parts: a simplified canary circuit for characterization and the original full circuit for computation. The canary circuit captures the essential noise characteristics of each quantum device independently, allowing the system to handle large circuits by characterizing devices in modular units rather than attempting to correct all errors simultaneously
Solution Approach 2:
The patent changes the gate set parameters of the canary circuit to use only Clifford gates, which are classically simulable and easier to execute on noisy hardware. This parameter change allows the canary circuit to be executed with higher reliability to characterize device noise, while the original circuit with its full gate set can then be executed using the noise characterizations obtained from the simplified canary circuit
3Device complexity
If quantum devices are used without considering individual noise properties, then device complexity is reduced, but execution fidelity is impacted in a unique way for each device
Solution Approach 1:
The patent performs preliminary execution of the canary circuit on each quantum device before executing the original circuit. This preliminary action characterizes the noise properties of each device by comparing canary circuit outputs against classical simulation results, storing this information in a noise characterization database that can then be used to correct subsequent circuit executions
Solution Approach 2:
The patent implements feedback by using the noise characterizations obtained from canary circuit execution to correct or compensate for errors in the original quantum circuit execution. The system continuously monitors device performance and adjusts error correction strategies based on the characterized noise properties, creating a closed-loop system that adapts to individual device behavior
Data Source
AI summary
A quantum computing system including a plurality of quantum computing resources, and at least one classical processor configured to: create and execute a canary circuit corresponding to the original quantum circuit on the at least one classical processor; identify a classical canary output; identify a canary ordering of quantum computing resources that increases a likelihood of generating the classical canary output on the plurality of quantum computing resources; execute the original quantum circuit on the plurality of quantum computing resources; identify a set of actual outputs generated by execution of the original quantum circuit on the plurality of quantum computing resources; associate an ordering of the plurality of quantum computing resources corresponding to each actual output of the set of actual outputs; and determine a correct output of the original quantum circuit based on comparing the ordering of the plurality of quantum computing resources with the canary ordering.