Echoed Cross-Resonance Gate Decoupling for Qubit Error Cancellation
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Solution Overview
Problem
Current implementations of cross-resonance gates in quantum computing suffer from coherent and incoherent error sources, particularly in superconducting qubits, leading to undesired couplings that limit the error rate and coherence of quantum operations.
Innovation Solution
Applying both cross-resonance and decoupling pulses to the target qubit in phase, with a 180-degree phase difference, to cancel undesired error sources and improve the fidelity of quantum gates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cross-resonance gates are implemented in quantum computing, then quantum gate operations can be performed, but coherent errors due to undesired couplings occur which limit error rate and computational power
Solution Approach 1:
The patent applies preliminary anti-action by introducing decoupling pulses before and during the cross-resonance gate operation to preemptively counteract coherent errors. The decoupling pulses are designed to cancel the undesired couplings that would otherwise cause errors during the gate operation, thereby improving reliability without sacrificing gate functionality.
Solution Approach 2:
The patent converts the harmful coherent errors into a benefit by using the same coupling mechanism that causes errors to also enable error cancellation. The decoupling pulses exploit the undesired couplings to generate compensating error terms that cancel the harmful coherent errors, effectively turning the harmful interaction into a useful error-correction mechanism.
2Reliability
If decoupling pulses are applied to cancel coherent errors, then error rate improves, but device complexity increases due to additional pulse sequences
Solution Approach 1:
The patent merges the decoupling pulse sequence with the existing cross-resonance gate operation by applying the decoupling pulses simultaneously with the gate pulses rather than as separate operations. This integration approach reduces the overall sequence complexity while maintaining the error cancellation benefit, as the decoupling and gate operations share the same temporal and spatial resources.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the impact of error sources on two-qubit gates, enhancing the computational power of quantum computers by improving the fidelity and error rate of quantum operations.
Implementation Method 1
The cross-resonance pulse propagates to the target qubit via a control qubit
Implementation Method 2
receiving both a phase-inverted cross-resonance pulse and a phase-inverted decoupling pulse at the target qubit
Data Source
AI summary
Systems, computer-implemented methods, and/or computer program products that can facilitate target qubit decoupling in an echoed cross-resonance gate are provided. According to an embodiment, a computer-implemented method can comprise receiving, by a system operatively coupled to a processor, both a cross-resonance pulse and a decoupling pulse at a target qubit. The cross-resonance pulse propagates to the target qubit via a control qubit. The computer-implemented method can further comprise receiving, by the system, a state inversion pulse at the control qubit. The computer-implemented method can further comprise receiving, by the system, both a phase-inverted cross-resonance pulse and a phase-inverted decoupling pulse at the target qubit. The phase-inverted cross-resonance pulse propagates to the target qubit via the control qubit.