Quantum Error Correction with Metastable States of Trapped Ions Using Erasure Conversion

TL;DR

This paper explores converting physical noise into erasures in trapped-ion quantum computers by encoding qubits into metastable states, potentially enhancing error correction performance compared to ground states.

Contribution

It proposes a detailed erasure-conversion scheme for metastable trapped-ion qubits and compares their performance with ground qubits under realistic conditions.

Findings

Metastable qubits may outperform ground qubits with higher laser power.

Erasure conversion improves quantum error correction performance.

Detailed error models for metastable states are developed.

Abstract

Erasures, or errors with known locations, are a more favorable type of error for quantum error-correcting codes than Pauli errors. Converting physical noise into erasures can significantly improve the performance of quantum error correction. Here we apply the idea of performing erasure conversion by encoding qubits into metastable atomic states, proposed by Wu, Kolkowitz, Puri, and Thompson [Nat. Comm. 13, 4657 (2022)], to trapped ions. We suggest an erasure-conversion scheme for metastable trapped-ion qubits and develop a detailed model of various types of errors. We then compare the logical performance of ground and metastable qubits on the surface code under various physical constraints, and conclude that metastable qubits may outperform ground qubits when the achievable laser power is higher for metastable qubits.