Demonstration of a Multiplexing Trapped Ion Quantum Processing Unit

TL;DR

This paper demonstrates a multiplexed trapped ion quantum processing unit that reduces wiring complexity while maintaining high-fidelity quantum operations, advancing scalable quantum computing technology.

Contribution

It introduces a time multiplexing control scheme for ion traps, enabling scalable quantum processing with fewer control lines and minimal impact on gate fidelity.

Findings

Motional heating rates below one phonon per second in both configurations.

Sampling intervals below 50 ms keep gate errors below 10^-4.

Multiplexing scheme is compatible with high-fidelity quantum operations.

Abstract

A fault-tolerant quantum computer is expected to require thousands of qubits. Trapped ion architectures provide a modular approach where the quantum register is divided into multiple subregisters connected by physically moving the corresponding ions. Transporting ions at scale comes with several challenges such as the need to connect thousands of control lines to an ion trap chip. Multiplexing the required control voltages from few input signals to multiple electrodes offers a solution to this wiring challenge. Here we demonstrate a quantum processing unit that combines a surface ion trap with a time multiplexer via a sample-and-hold technique that initially charges electrodes to fixed voltages and disconnects them during qubit operations. We characterize the unit's performance by measuring motional heating rates below one phonon per second in both open and closed switch configurations. We further characterize the sample and hold process and find that sampling intervals below 50 ms are sufficient to keep expected gate errors from decaying charges during the hold phase below $10^{-4}$. Our results indicate that the multiplexing scheme is compatible with high-fidelity operations.