Error-mitigated quantum gates exceeding physical fidelities in a trapped-ion system.

Area of Science:

• Quantum Computing
• Quantum Information Science

Background:

• Quantum applications rely on estimating expectation values, which are susceptible to operational and environmental errors.
• Quantum error correction is resource-intensive and not feasible for near-term quantum technologies.
• Quantum error mitigation offers a qubit-efficient alternative to combat errors.

Purpose of the Study:

• To benchmark a quantum error mitigation technique based on probabilistic error cancellation.
• To evaluate the performance of this technique in a trapped-ion quantum system.
• To demonstrate the potential for high-fidelity quantum computations on noisy, near-term devices.

Main Methods:

• Implemented a quantum error mitigation technique utilizing probabilistic error cancellation.
• Benchmarked the technique on a trapped-ion quantum processor.
• Programmed quantum circuits to assess effective gate fidelities.

Main Results:

• Effective gate fidelities surpassed physical fidelities, indicating successful error suppression.
• Error rates for single-qubit gates were reduced from 1.10 × 10^-3 to 1.44 × 10^-5.
• Error rates for two-qubit gates were reduced from 0.99 × 10^-2 to 0.96 × 10^-3.

Conclusions:

• Probabilistic error cancellation effectively mitigates errors in trapped-ion systems.
• The demonstrated technique surpasses the break-even point for eliminating gate errors.
• This approach paves the way for high-fidelity quantum computations on near-term noisy quantum devices.