High-fidelity laser-free universal control of two trapped ion qubits

TL;DR

This paper introduces a laser-free method for high-fidelity, universal control of two trapped ion qubits using microwave and radiofrequency magnetic fields, enabling robust entanglement and individual qubit operations.

Contribution

The authors demonstrate a novel laser-free control scheme for trapped ion qubits that achieves high-fidelity entanglement and is scalable to multiple ion pairs.

Findings

Achieved fidelities between 0.9964 and 1 for entangled states.

Demonstrated robustness against decoherence sources.

Compatible with various trapped ion species.

Abstract

Universal control of multiple qubits -- the ability to entangle qubits and to perform arbitrary individual qubit operations -- is a fundamental resource for quantum computation, simulation, and networking. Here, we implement a new laser-free scheme for universal control of trapped ion qubits based on microwave magnetic fields and radiofrequency magnetic field gradients. We demonstrate high-fidelity entanglement and individual control by creating symmetric and antisymmetric two-qubit maximally entangled states with fidelities in the intervals [0.9983, 1] and [0.9964, 0.9988], respectively, at 68% confidence, corrected for state initialization error. This technique is robust against multiple sources of decoherence, usable with essentially any trapped ion species, and has the potential to perform simultaneous entangling operations on many pairs of ions without increasing control signal power or complexity.