High-Fidelity, Single-Shot, Quantum-Logic-Assisted Readout in a Mixed-Species Ion Chain

TL;DR

This paper demonstrates a high-fidelity, single-shot quantum measurement technique in a mixed-species ion chain, utilizing sympathetic cooling and quantum logic to improve measurement accuracy and reduce errors in quantum information processing.

Contribution

The study introduces a novel quantum-logic-assisted readout method in a mixed-species ion chain with enhanced accuracy and reduced photon scattering errors.

Findings

Achieved 96(1)% measurement accuracy of ion state populations.

Demonstrated low motional heating rate enabling effective quantum state transfer.

Showed potential for reducing measurement-induced errors in quantum processors.

Abstract

We use a co-trapped ion ($^{88}\mathrm{Sr}^{+}$) to sympathetically cool and measure the quantum state populations of a memory-qubit ion of a different atomic species ($^{40}\mathrm{Ca}^{+}$) in a cryogenic, surface-electrode ion trap. Due in part to the low motional heating rate demonstrated here, the state populations of the memory ion can be transferred to the auxiliary ion by using the shared motion as a quantum state bus and measured with an average accuracy of 96(1)%. This scheme can be used in quantum information processors to reduce photon-scattering-induced error in unmeasured memory qubits.