Two-Qubit Gate Frequency Optimization via Batch Noise Injection
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Solution Overview
Problem
Achieving high-fidelity entangling gates in large-scale quantum computing systems is challenging due to noise and parameter drifts, which affect the robustness and scalability of two-qubit gates in trapped ion systems.
Innovation Solution
The method involves optimizing frequency modulated gates using batch optimization techniques, applying intentional noise to a subset of qubits and determining an optimized frequency using a numerical optimizer to correct phase deviations and improve gate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional frequency modulation schemes are used for two-qubit gates, then the gate operation can be performed, but the gate fidelity decreases due to noise and parameter drifts in large-scale systems
Solution Approach 1:
The patent applies preliminary action by performing batch optimization before actual gate operations to determine optimal frequency parameters. The system pre-calculates the frequency modulation parameters that will maximize gate fidelity across a range of systematic errors, so when the actual gate operation occurs, the parameters are already optimized to compensate for expected noise and drifts, thereby improving reliability without adding complexity during operation
Solution Approach 2:
The patent implements parameter changes by systematically varying the frequency modulation parameters across batches of optimization iterations. By exploring different frequency parameters and their effects on gate fidelity under various noise conditions, the system identifies the optimal parameter set that maintains high fidelity despite parameter drifts and noise in large-scale trapped ion systems
2Adaptability or versatility
If the number of qubits is increased to achieve scalability, then more quantum operations can be performed, but maintaining high-fidelity entangling gates becomes more difficult
Solution Approach 1:
The patent addresses the scalability-fidelity contradiction by implementing batch optimization that systematically adjusts frequency modulation parameters based on the number of ions in the chain. The optimization process adapts parameters such as modulation depth, frequency offset, and pulse duration to maintain high entangling gate fidelity regardless of system size, enabling the system to scale from 2-ion to 17-ion chains while preserving gate quality
Solution Approach 2:
The system performs preliminary batch optimization to pre-determine the optimal frequency parameters for entangling gates before execution. This preliminary calculation accounts for the specific number of ions and their interactions, allowing the system to scale to larger ion chains while maintaining high gate fidelity through pre-computed parameters that compensate for increased complexity in multi-ion systems
3Speed
If laser power is increased to improve gate operation, then gate speed can be enhanced, but the system becomes more sensitive to noise and parameter drifts
Solution Approach 1:
The patent resolves the speed-noise contradiction by optimizing laser parameter profiles through batch optimization. Instead of simply increasing laser power, the system optimizes the temporal and spectral distribution of laser parameters, including modulation depth, frequency chirp rate, and pulse shaping, to achieve fast gate operations while maintaining signal-to-noise ratio and minimizing laser-induced heating and decoherence
Solution Approach 2:
The patent applies dynamics by implementing time-dependent frequency modulation of the laser fields during gate operations. The frequency parameters are dynamically adjusted during the gate sequence to maintain resonance conditions and maximize coupling efficiency, thereby achieving fast operations without requiring excessive laser power that would amplify noise and parameter drifts
Data Source
AI summary
The present disclosure describes techniques for optimizing two-qubit gates performance in a quantum circuit of a quantum computing system. A quantum computing system selects, from qubits in the quantum circuit, a pair of target qubits on which to perform a quantum gate operation. The quantum computing system selects, from the plurality of qubits, a second plurality of qubits on which to introduce an intentional noise. The intentional noise is applied to the second plurality of qubits via a numerical optimizer. An optimized frequency is determined based on the applied intentional noise. The quantum gate operation is performed by modifying the pair of target qubits frequency to the optimized frequency.