Composite Quantum Gate Pulse Compensation for Settling Errors
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Solution Overview
Problem
Quantum computing systems face challenges in precisely measuring and compensating for non-idealities in the transfer function between control electronics and qubits, leading to long settling times and increased errors in downstream quantum gates, particularly affecting coupler quantum gates due to sensitivity to control pulse amplitudes.
Innovation Solution
A control scheme is implemented to compensate for settling times by adjusting the amplitude of subsequent control pulses based on the amplitude of preceding pulses, using a model to determine optimal adjustments for each gate in a sequence, reducing the impact of settling times on downstream quantum gates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional control pulses are applied to implement sequential quantum gates, then quantum gate operations can be performed, but settling time effects from preceding pulses cause errors in downstream gates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-distorting control pulse amplitudes based on a model of settling time effects. Before executing a sequence of quantum gates, the system computes adjusted pulse amplitudes that compensate for expected settling time interference from preceding pulses. This allows downstream gates to receive pre-compensated pulses that account for residual effects from previous operations, thereby reducing errors without requiring extended settling times.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the amplitude parameter of control pulses based on the amplitude of preceding pulses and a model of settling time behavior. The system modifies pulse parameters (amplitude, and potentially duration) to compensate for settling time effects, transforming the control pulse characteristics to achieve accurate downstream gate operations while maintaining shorter inter-gate intervals.
2Productivity
If settling time is reduced to increase processing speed, then productivity improves, but measurement precision of transfer function non-idealities deteriorates
Solution Approach 1:
The patent employs feedback by using a model of settling time effects that is derived from measured transfer function non-idealities. The system measures the transfer function characteristics, builds a compensatory model, and then applies this model to adjust subsequent control pulses. This feedback loop allows the system to maintain high processing speeds while compensating for settling time effects, as the model enables prediction and correction without requiring extended measurement or settling periods.
Solution Approach 2:
The system performs preliminary characterization of the transfer function and its non-idealities, storing this information in a model that is then used to pre-compensate control pulses. By conducting the measurement and model creation phase separately from the execution phase, the system can achieve high-speed processing during actual quantum gate sequences while having already captured the necessary precision data during the initial characterization phase.
3Reliability
If control pulse amplitudes are adjusted to compensate for settling times, then accuracy of downstream gates improves, but device complexity increases
Solution Approach 1:
The patent focuses parameter changes primarily on the amplitude parameter of control pulses, which is a single, well-defined parameter that can be adjusted through software or control electronics. By concentrating the compensation effort on amplitude adjustment rather than modifying multiple parameters or hardware components, the system achieves improved downstream gate accuracy while minimizing increases in device complexity. The approach leverages existing control infrastructure with software-based amplitude modulation.
Solution Approach 2:
The patent replaces potential hardware modifications with software-based control pulse adjustment. Instead of introducing additional physical components or hardware mechanisms to compensate for settling times, the system uses computational models and software algorithms to calculate and apply amplitude corrections. This substitution of software control for hardware complexity achieves the desired accuracy improvement while keeping the physical device architecture relatively simple.
Data Source
AI summary
Quantum computing systems and methods are provided. In one example, the method includes applying a first control pulse to implement a first quantum gate in a set of sequential quantum gates implemented in a quantum computing system. The first control pulse has a first amplitude. Subsequent to applying the first control pulse, the method includes applying a second control pulse to implement a second quantum gate in the set of sequential quantum gates. The second control pulse has a second amplitude. The second amplitude is determined based at least in part on the first amplitude of the first control pulse, for instance, to reduce an effect attributable to a settling time associated with the first control pulse during applying of the second control pulse.