Barium Magnesium Alloy as Source of Atomic Ba for Ion Trapping

TL;DR

This paper introduces a practical method using barium magnesium alloy in resistively heated ovens as a stable, less reactive source of barium vapor for ion trapping in quantum computing, matching the performance of elemental barium sources.

Contribution

The study demonstrates that BaMg alloy can effectively replace elemental barium as a stable, less reactive barium source for ion trapping applications.

Findings

BaMg alloy produces comparable barium vapor pressures to metallic barium.

Reliable trapping of 138Ba+ ions was achieved with BaMg source.

BaMg alloy is less reactive and resistant to oxidation in air.

Abstract

Trapped atomic ion qubits exhibit long coherence times and high fidelity qubit state preparation, manipulation and detection, making them well-suited for scalable quantum computing applications. Among several atomic species used in quantum computing and other application, singly-charged ions of barium stand out due to their long wavelength transitions and the presence of very long-lived metastable internal states. However, elemental barium is a highly reactive metal making it experimentally difficult to work with when making atomic beam sources. In this paper, we demonstrate a method of using resistively heated ovens loaded with a barium magnesium alloy (BaMg) as a source of barium for ion traps. This alloy is not very chemically reactive and does not oxidize in air. We found that a sample of BaMg in a resistively heated oven produced barium vapor pressures on the same order as a metallic barium sample prepared the same way. Two separate ovens, one with a sample of BaMg and one with metallic barium, were used as source for an ion trap. We observed reliable trapping of 138Ba+ ions both with the elemental barium source, and the BaMg source.