Ba-133: the Goldilocks qubit?

133Ba+, a manufacturered radioisotope, possesses several unique and desirable properties which are not found in any naturally occurring species, which make it a nearly ideal qubit.  Specifically, the barium electronic structure provides transitions in the visible part of the electromagnetic spectrum, enabling the use of the high-power lasers, low-loss fibers, high quantum efficiency detectors, and other optical equipment not available to many ion species currently in use.  The nuclear structure of 133Ba+ provides a robust hyperfine clock state qubit that is easy to initialize and detect, yet protects the qubit coherence during shuttling and storage.  These features make it compatible with existing traps and in many ways superior to species currently in use, particularly for a QCCD architecture and for remote linking via photons. 

This project, in collaboration with Prof. Wes Campbell, has trapped and laser cooled this exciting isotope. We are manipulating the qubit levels in this ion and we recently realized the highest fidelity single qubit on any quantum information platform (F = 0.9997 as of 8/8/18).

Pictures: Left: laser setup for laser-cooling any isotope of barium atomic ions.  Right: chain of laser-cooled 133Ba+ ions.

Basic microwave manipulation of the 133Ba+ hyperfine qubit using a microwave source at 9.92546 GHz.

Group Members

Justin Christensen- Graduate Student [physics.justin.christensen](jchristensen)
email address: [@gmail](

Group Alumni

David Hucul- Postdoctoral Researcher [dhucul](dhucul)

Tyler Jackson- Undergraduate Researcher
Calvin He- Undergraduate Researcher
Rudy Pei- Undergraduate Researcher

Group Publications

"Spectroscopy of a synthetic trapped ion qubit," D. Hucul, J.E. Christensen, E.R. Hudson, W.C. Campbell, Phys. Rev. Lett. 119, 100501 (2017)
                                                                            ArXiv preprint: arXiv:1705.09736 (2017)
                                                                            News & Commentary: Synopsis: Radioactive Qubits

Group Talks & Presentations

"Ba-133: the Goldilocks qubit?" D. Hucul

For Visitors

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